Commit | Line | Data |
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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 IRQ_WORK |
24 | bool | |
e360adbe | 25 | |
1dbdc6f1 DD |
26 | config BUILDTIME_EXTABLE_SORT |
27 | bool | |
28 | ||
ff0cfc66 | 29 | menu "General setup" |
1da177e4 | 30 | |
1da177e4 LT |
31 | config BROKEN |
32 | bool | |
1da177e4 LT |
33 | |
34 | config BROKEN_ON_SMP | |
35 | bool | |
36 | depends on BROKEN || !SMP | |
37 | default y | |
38 | ||
1da177e4 LT |
39 | config INIT_ENV_ARG_LIMIT |
40 | int | |
dd673bca AB |
41 | default 32 if !UML |
42 | default 128 if UML | |
1da177e4 | 43 | help |
34ad92c2 RD |
44 | Maximum of each of the number of arguments and environment |
45 | variables passed to init from the kernel command line. | |
1da177e4 | 46 | |
1da177e4 | 47 | |
84336466 RM |
48 | config CROSS_COMPILE |
49 | string "Cross-compiler tool prefix" | |
50 | help | |
51 | Same as running 'make CROSS_COMPILE=prefix-' but stored for | |
52 | default make runs in this kernel build directory. You don't | |
53 | need to set this unless you want the configured kernel build | |
54 | directory to select the cross-compiler automatically. | |
55 | ||
4bb16672 JS |
56 | config COMPILE_TEST |
57 | bool "Compile also drivers which will not load" | |
58 | default n | |
59 | help | |
60 | Some drivers can be compiled on a different platform than they are | |
61 | intended to be run on. Despite they cannot be loaded there (or even | |
62 | when they load they cannot be used due to missing HW support), | |
63 | developers still, opposing to distributors, might want to build such | |
64 | drivers to compile-test them. | |
65 | ||
66 | If you are a developer and want to build everything available, say Y | |
67 | here. If you are a user/distributor, say N here to exclude useless | |
68 | drivers to be distributed. | |
69 | ||
1da177e4 LT |
70 | config LOCALVERSION |
71 | string "Local version - append to kernel release" | |
72 | help | |
73 | Append an extra string to the end of your kernel version. | |
74 | This will show up when you type uname, for example. | |
75 | The string you set here will be appended after the contents of | |
76 | any files with a filename matching localversion* in your | |
77 | object and source tree, in that order. Your total string can | |
78 | be a maximum of 64 characters. | |
79 | ||
aaebf433 RA |
80 | config LOCALVERSION_AUTO |
81 | bool "Automatically append version information to the version string" | |
82 | default y | |
83 | help | |
84 | This will try to automatically determine if the current tree is a | |
6e5a5420 RD |
85 | release tree by looking for git tags that belong to the current |
86 | top of tree revision. | |
aaebf433 RA |
87 | |
88 | A string of the format -gxxxxxxxx will be added to the localversion | |
6e5a5420 | 89 | if a git-based tree is found. The string generated by this will be |
aaebf433 | 90 | appended after any matching localversion* files, and after the value |
6e5a5420 | 91 | set in CONFIG_LOCALVERSION. |
aaebf433 | 92 | |
6e5a5420 RD |
93 | (The actual string used here is the first eight characters produced |
94 | by running the command: | |
95 | ||
96 | $ git rev-parse --verify HEAD | |
97 | ||
98 | which is done within the script "scripts/setlocalversion".) | |
aaebf433 | 99 | |
2e9f3bdd PA |
100 | config HAVE_KERNEL_GZIP |
101 | bool | |
102 | ||
103 | config HAVE_KERNEL_BZIP2 | |
104 | bool | |
105 | ||
106 | config HAVE_KERNEL_LZMA | |
107 | bool | |
108 | ||
3ebe1243 LC |
109 | config HAVE_KERNEL_XZ |
110 | bool | |
111 | ||
7dd65feb AT |
112 | config HAVE_KERNEL_LZO |
113 | bool | |
114 | ||
e76e1fdf KL |
115 | config HAVE_KERNEL_LZ4 |
116 | bool | |
117 | ||
30d65dbf | 118 | choice |
2e9f3bdd PA |
119 | prompt "Kernel compression mode" |
120 | default KERNEL_GZIP | |
2d3c6275 | 121 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 |
2e9f3bdd | 122 | help |
30d65dbf AK |
123 | The linux kernel is a kind of self-extracting executable. |
124 | Several compression algorithms are available, which differ | |
125 | in efficiency, compression and decompression speed. | |
126 | Compression speed is only relevant when building a kernel. | |
127 | Decompression speed is relevant at each boot. | |
128 | ||
129 | If you have any problems with bzip2 or lzma compressed | |
130 | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older | |
131 | version of this functionality (bzip2 only), for 2.4, was | |
132 | supplied by Christian Ludwig) | |
133 | ||
134 | High compression options are mostly useful for users, who | |
135 | are low on disk space (embedded systems), but for whom ram | |
136 | size matters less. | |
137 | ||
138 | If in doubt, select 'gzip' | |
139 | ||
140 | config KERNEL_GZIP | |
2e9f3bdd PA |
141 | bool "Gzip" |
142 | depends on HAVE_KERNEL_GZIP | |
143 | help | |
7dd65feb AT |
144 | The old and tried gzip compression. It provides a good balance |
145 | between compression ratio and decompression speed. | |
30d65dbf AK |
146 | |
147 | config KERNEL_BZIP2 | |
148 | bool "Bzip2" | |
2e9f3bdd | 149 | depends on HAVE_KERNEL_BZIP2 |
30d65dbf AK |
150 | help |
151 | Its compression ratio and speed is intermediate. | |
0a4dd35c | 152 | Decompression speed is slowest among the choices. The kernel |
2e9f3bdd PA |
153 | size is about 10% smaller with bzip2, in comparison to gzip. |
154 | Bzip2 uses a large amount of memory. For modern kernels you | |
155 | will need at least 8MB RAM or more for booting. | |
30d65dbf AK |
156 | |
157 | config KERNEL_LZMA | |
2e9f3bdd PA |
158 | bool "LZMA" |
159 | depends on HAVE_KERNEL_LZMA | |
160 | help | |
0a4dd35c RD |
161 | This compression algorithm's ratio is best. Decompression speed |
162 | is between gzip and bzip2. Compression is slowest. | |
163 | The kernel size is about 33% smaller with LZMA in comparison to gzip. | |
30d65dbf | 164 | |
3ebe1243 LC |
165 | config KERNEL_XZ |
166 | bool "XZ" | |
167 | depends on HAVE_KERNEL_XZ | |
168 | help | |
169 | XZ uses the LZMA2 algorithm and instruction set specific | |
170 | BCJ filters which can improve compression ratio of executable | |
171 | code. The size of the kernel is about 30% smaller with XZ in | |
172 | comparison to gzip. On architectures for which there is a BCJ | |
173 | filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ | |
174 | will create a few percent smaller kernel than plain LZMA. | |
175 | ||
176 | The speed is about the same as with LZMA: The decompression | |
177 | speed of XZ is better than that of bzip2 but worse than gzip | |
178 | and LZO. Compression is slow. | |
179 | ||
7dd65feb AT |
180 | config KERNEL_LZO |
181 | bool "LZO" | |
182 | depends on HAVE_KERNEL_LZO | |
183 | help | |
0a4dd35c | 184 | Its compression ratio is the poorest among the choices. The kernel |
681b3049 | 185 | size is about 10% bigger than gzip; however its speed |
7dd65feb AT |
186 | (both compression and decompression) is the fastest. |
187 | ||
e76e1fdf KL |
188 | config KERNEL_LZ4 |
189 | bool "LZ4" | |
190 | depends on HAVE_KERNEL_LZ4 | |
191 | help | |
192 | LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. | |
193 | A preliminary version of LZ4 de/compression tool is available at | |
194 | <https://code.google.com/p/lz4/>. | |
195 | ||
196 | Its compression ratio is worse than LZO. The size of the kernel | |
197 | is about 8% bigger than LZO. But the decompression speed is | |
198 | faster than LZO. | |
199 | ||
30d65dbf AK |
200 | endchoice |
201 | ||
bd5dc17b JT |
202 | config DEFAULT_HOSTNAME |
203 | string "Default hostname" | |
204 | default "(none)" | |
205 | help | |
206 | This option determines the default system hostname before userspace | |
207 | calls sethostname(2). The kernel traditionally uses "(none)" here, | |
208 | but you may wish to use a different default here to make a minimal | |
209 | system more usable with less configuration. | |
210 | ||
1da177e4 LT |
211 | config SWAP |
212 | bool "Support for paging of anonymous memory (swap)" | |
9361401e | 213 | depends on MMU && BLOCK |
1da177e4 LT |
214 | default y |
215 | help | |
216 | This option allows you to choose whether you want to have support | |
92c3504e | 217 | for so called swap devices or swap files in your kernel that are |
1da177e4 LT |
218 | used to provide more virtual memory than the actual RAM present |
219 | in your computer. If unsure say Y. | |
220 | ||
221 | config SYSVIPC | |
222 | bool "System V IPC" | |
1da177e4 LT |
223 | ---help--- |
224 | Inter Process Communication is a suite of library functions and | |
225 | system calls which let processes (running programs) synchronize and | |
226 | exchange information. It is generally considered to be a good thing, | |
227 | and some programs won't run unless you say Y here. In particular, if | |
228 | you want to run the DOS emulator dosemu under Linux (read the | |
229 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), | |
230 | you'll need to say Y here. | |
231 | ||
232 | You can find documentation about IPC with "info ipc" and also in | |
233 | section 6.4 of the Linux Programmer's Guide, available from | |
234 | <http://www.tldp.org/guides.html>. | |
235 | ||
a5494dcd EB |
236 | config SYSVIPC_SYSCTL |
237 | bool | |
238 | depends on SYSVIPC | |
239 | depends on SYSCTL | |
240 | default y | |
241 | ||
1da177e4 LT |
242 | config POSIX_MQUEUE |
243 | bool "POSIX Message Queues" | |
19c92399 | 244 | depends on NET |
1da177e4 LT |
245 | ---help--- |
246 | POSIX variant of message queues is a part of IPC. In POSIX message | |
247 | queues every message has a priority which decides about succession | |
248 | of receiving it by a process. If you want to compile and run | |
249 | programs written e.g. for Solaris with use of its POSIX message | |
b0e37650 | 250 | queues (functions mq_*) say Y here. |
1da177e4 LT |
251 | |
252 | POSIX message queues are visible as a filesystem called 'mqueue' | |
253 | and can be mounted somewhere if you want to do filesystem | |
254 | operations on message queues. | |
255 | ||
256 | If unsure, say Y. | |
257 | ||
bdc8e5f8 SH |
258 | config POSIX_MQUEUE_SYSCTL |
259 | bool | |
260 | depends on POSIX_MQUEUE | |
261 | depends on SYSCTL | |
262 | default y | |
263 | ||
391dc69c FW |
264 | config FHANDLE |
265 | bool "open by fhandle syscalls" | |
266 | select EXPORTFS | |
267 | help | |
268 | If you say Y here, a user level program will be able to map | |
269 | file names to handle and then later use the handle for | |
270 | different file system operations. This is useful in implementing | |
271 | userspace file servers, which now track files using handles instead | |
272 | of names. The handle would remain the same even if file names | |
273 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) | |
274 | syscalls. | |
275 | ||
276 | config AUDIT | |
277 | bool "Auditing support" | |
278 | depends on NET | |
279 | help | |
280 | Enable auditing infrastructure that can be used with another | |
281 | kernel subsystem, such as SELinux (which requires this for | |
282 | logging of avc messages output). Does not do system-call | |
283 | auditing without CONFIG_AUDITSYSCALL. | |
284 | ||
285 | config AUDITSYSCALL | |
286 | bool "Enable system-call auditing support" | |
527973c8 | 287 | depends on AUDIT && (X86 || PARISC || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) |
391dc69c FW |
288 | default y if SECURITY_SELINUX |
289 | help | |
290 | Enable low-overhead system-call auditing infrastructure that | |
291 | can be used independently or with another kernel subsystem, | |
292 | such as SELinux. | |
293 | ||
294 | config AUDIT_WATCH | |
295 | def_bool y | |
296 | depends on AUDITSYSCALL | |
297 | select FSNOTIFY | |
298 | ||
299 | config AUDIT_TREE | |
300 | def_bool y | |
301 | depends on AUDITSYSCALL | |
302 | select FSNOTIFY | |
303 | ||
391dc69c FW |
304 | source "kernel/irq/Kconfig" |
305 | source "kernel/time/Kconfig" | |
306 | ||
307 | menu "CPU/Task time and stats accounting" | |
308 | ||
abf917cd FW |
309 | config VIRT_CPU_ACCOUNTING |
310 | bool | |
311 | ||
fdf9c356 FW |
312 | choice |
313 | prompt "Cputime accounting" | |
314 | default TICK_CPU_ACCOUNTING if !PPC64 | |
02fc8d37 | 315 | default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
fdf9c356 FW |
316 | |
317 | # Kind of a stub config for the pure tick based cputime accounting | |
318 | config TICK_CPU_ACCOUNTING | |
319 | bool "Simple tick based cputime accounting" | |
c58b0df1 | 320 | depends on !S390 && !NO_HZ_FULL |
fdf9c356 FW |
321 | help |
322 | This is the basic tick based cputime accounting that maintains | |
323 | statistics about user, system and idle time spent on per jiffies | |
324 | granularity. | |
325 | ||
326 | If unsure, say Y. | |
327 | ||
abf917cd | 328 | config VIRT_CPU_ACCOUNTING_NATIVE |
b952741c | 329 | bool "Deterministic task and CPU time accounting" |
c58b0df1 | 330 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
abf917cd | 331 | select VIRT_CPU_ACCOUNTING |
b952741c FW |
332 | help |
333 | Select this option to enable more accurate task and CPU time | |
334 | accounting. This is done by reading a CPU counter on each | |
335 | kernel entry and exit and on transitions within the kernel | |
336 | between system, softirq and hardirq state, so there is a | |
337 | small performance impact. In the case of s390 or IBM POWER > 5, | |
338 | this also enables accounting of stolen time on logically-partitioned | |
339 | systems. | |
340 | ||
abf917cd FW |
341 | config VIRT_CPU_ACCOUNTING_GEN |
342 | bool "Full dynticks CPU time accounting" | |
ff3fb254 | 343 | depends on HAVE_CONTEXT_TRACKING |
554b0004 | 344 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
abf917cd FW |
345 | select VIRT_CPU_ACCOUNTING |
346 | select CONTEXT_TRACKING | |
347 | help | |
348 | Select this option to enable task and CPU time accounting on full | |
349 | dynticks systems. This accounting is implemented by watching every | |
350 | kernel-user boundaries using the context tracking subsystem. | |
351 | The accounting is thus performed at the expense of some significant | |
352 | overhead. | |
353 | ||
354 | For now this is only useful if you are working on the full | |
355 | dynticks subsystem development. | |
356 | ||
357 | If unsure, say N. | |
358 | ||
fdf9c356 FW |
359 | config IRQ_TIME_ACCOUNTING |
360 | bool "Fine granularity task level IRQ time accounting" | |
c58b0df1 | 361 | depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL |
fdf9c356 FW |
362 | help |
363 | Select this option to enable fine granularity task irq time | |
364 | accounting. This is done by reading a timestamp on each | |
365 | transitions between softirq and hardirq state, so there can be a | |
366 | small performance impact. | |
367 | ||
368 | If in doubt, say N here. | |
369 | ||
370 | endchoice | |
371 | ||
1da177e4 LT |
372 | config BSD_PROCESS_ACCT |
373 | bool "BSD Process Accounting" | |
374 | help | |
375 | If you say Y here, a user level program will be able to instruct the | |
376 | kernel (via a special system call) to write process accounting | |
377 | information to a file: whenever a process exits, information about | |
378 | that process will be appended to the file by the kernel. The | |
379 | information includes things such as creation time, owning user, | |
380 | command name, memory usage, controlling terminal etc. (the complete | |
381 | list is in the struct acct in <file:include/linux/acct.h>). It is | |
382 | up to the user level program to do useful things with this | |
383 | information. This is generally a good idea, so say Y. | |
384 | ||
385 | config BSD_PROCESS_ACCT_V3 | |
386 | bool "BSD Process Accounting version 3 file format" | |
387 | depends on BSD_PROCESS_ACCT | |
388 | default n | |
389 | help | |
390 | If you say Y here, the process accounting information is written | |
391 | in a new file format that also logs the process IDs of each | |
392 | process and it's parent. Note that this file format is incompatible | |
393 | with previous v0/v1/v2 file formats, so you will need updated tools | |
394 | for processing it. A preliminary version of these tools is available | |
37a4c940 | 395 | at <http://www.gnu.org/software/acct/>. |
1da177e4 | 396 | |
c757249a | 397 | config TASKSTATS |
19c92399 | 398 | bool "Export task/process statistics through netlink" |
c757249a SN |
399 | depends on NET |
400 | default n | |
401 | help | |
402 | Export selected statistics for tasks/processes through the | |
403 | generic netlink interface. Unlike BSD process accounting, the | |
404 | statistics are available during the lifetime of tasks/processes as | |
405 | responses to commands. Like BSD accounting, they are sent to user | |
406 | space on task exit. | |
407 | ||
408 | Say N if unsure. | |
409 | ||
ca74e92b | 410 | config TASK_DELAY_ACCT |
19c92399 | 411 | bool "Enable per-task delay accounting" |
6f44993f | 412 | depends on TASKSTATS |
ca74e92b SN |
413 | help |
414 | Collect information on time spent by a task waiting for system | |
415 | resources like cpu, synchronous block I/O completion and swapping | |
416 | in pages. Such statistics can help in setting a task's priorities | |
417 | relative to other tasks for cpu, io, rss limits etc. | |
418 | ||
419 | Say N if unsure. | |
420 | ||
18f705f4 | 421 | config TASK_XACCT |
19c92399 | 422 | bool "Enable extended accounting over taskstats" |
18f705f4 AD |
423 | depends on TASKSTATS |
424 | help | |
425 | Collect extended task accounting data and send the data | |
426 | to userland for processing over the taskstats interface. | |
427 | ||
428 | Say N if unsure. | |
429 | ||
430 | config TASK_IO_ACCOUNTING | |
19c92399 | 431 | bool "Enable per-task storage I/O accounting" |
18f705f4 AD |
432 | depends on TASK_XACCT |
433 | help | |
434 | Collect information on the number of bytes of storage I/O which this | |
435 | task has caused. | |
436 | ||
437 | Say N if unsure. | |
438 | ||
391dc69c | 439 | endmenu # "CPU/Task time and stats accounting" |
d9817ebe | 440 | |
c903ff83 MT |
441 | menu "RCU Subsystem" |
442 | ||
443 | choice | |
444 | prompt "RCU Implementation" | |
31c9a24e | 445 | default TREE_RCU |
c903ff83 | 446 | |
c903ff83 MT |
447 | config TREE_RCU |
448 | bool "Tree-based hierarchical RCU" | |
687d7a96 | 449 | depends on !PREEMPT && SMP |
016a8d5b | 450 | select IRQ_WORK |
c903ff83 MT |
451 | help |
452 | This option selects the RCU implementation that is | |
453 | designed for very large SMP system with hundreds or | |
c17ef453 PM |
454 | thousands of CPUs. It also scales down nicely to |
455 | smaller systems. | |
c903ff83 | 456 | |
f41d911f | 457 | config TREE_PREEMPT_RCU |
a57eb940 | 458 | bool "Preemptible tree-based hierarchical RCU" |
9fc52d83 | 459 | depends on PREEMPT |
53614714 | 460 | select IRQ_WORK |
f41d911f PM |
461 | help |
462 | This option selects the RCU implementation that is | |
463 | designed for very large SMP systems with hundreds or | |
464 | thousands of CPUs, but for which real-time response | |
bbe3eae8 PM |
465 | is also required. It also scales down nicely to |
466 | smaller systems. | |
f41d911f | 467 | |
9fc52d83 PM |
468 | Select this option if you are unsure. |
469 | ||
9b1d82fa PM |
470 | config TINY_RCU |
471 | bool "UP-only small-memory-footprint RCU" | |
8008e129 | 472 | depends on !PREEMPT && !SMP |
9b1d82fa PM |
473 | help |
474 | This option selects the RCU implementation that is | |
475 | designed for UP systems from which real-time response | |
476 | is not required. This option greatly reduces the | |
477 | memory footprint of RCU. | |
478 | ||
c903ff83 MT |
479 | endchoice |
480 | ||
a57eb940 | 481 | config PREEMPT_RCU |
127781d1 | 482 | def_bool TREE_PREEMPT_RCU |
a57eb940 PM |
483 | help |
484 | This option enables preemptible-RCU code that is common between | |
485 | the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. | |
486 | ||
6bfc09e2 PM |
487 | config RCU_STALL_COMMON |
488 | def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE ) | |
489 | help | |
490 | This option enables RCU CPU stall code that is common between | |
491 | the TINY and TREE variants of RCU. The purpose is to allow | |
492 | the tiny variants to disable RCU CPU stall warnings, while | |
493 | making these warnings mandatory for the tree variants. | |
494 | ||
91d1aa43 FW |
495 | config CONTEXT_TRACKING |
496 | bool | |
497 | ||
2b1d5024 FW |
498 | config RCU_USER_QS |
499 | bool "Consider userspace as in RCU extended quiescent state" | |
91d1aa43 FW |
500 | depends on HAVE_CONTEXT_TRACKING && SMP |
501 | select CONTEXT_TRACKING | |
2b1d5024 FW |
502 | help |
503 | This option sets hooks on kernel / userspace boundaries and | |
504 | puts RCU in extended quiescent state when the CPU runs in | |
505 | userspace. It means that when a CPU runs in userspace, it is | |
506 | excluded from the global RCU state machine and thus doesn't | |
af71befa | 507 | try to keep the timer tick on for RCU. |
2b1d5024 | 508 | |
d677124b | 509 | Unless you want to hack and help the development of the full |
91d1aa43 | 510 | dynticks mode, you shouldn't enable this option. It also |
af71befa | 511 | adds unnecessary overhead. |
d677124b FW |
512 | |
513 | If unsure say N | |
514 | ||
91d1aa43 FW |
515 | config CONTEXT_TRACKING_FORCE |
516 | bool "Force context tracking" | |
517 | depends on CONTEXT_TRACKING | |
d84d27a4 | 518 | default y if !NO_HZ_FULL |
1fd2b442 | 519 | help |
d84d27a4 FW |
520 | The major pre-requirement for full dynticks to work is to |
521 | support the context tracking subsystem. But there are also | |
522 | other dependencies to provide in order to make the full | |
523 | dynticks working. | |
524 | ||
525 | This option stands for testing when an arch implements the | |
526 | context tracking backend but doesn't yet fullfill all the | |
527 | requirements to make the full dynticks feature working. | |
528 | Without the full dynticks, there is no way to test the support | |
529 | for context tracking and the subsystems that rely on it: RCU | |
530 | userspace extended quiescent state and tickless cputime | |
531 | accounting. This option copes with the absence of the full | |
532 | dynticks subsystem by forcing the context tracking on all | |
533 | CPUs in the system. | |
534 | ||
99c8b1ea | 535 | Say Y only if you're working on the development of an |
d84d27a4 FW |
536 | architecture backend for the context tracking. |
537 | ||
538 | Say N otherwise, this option brings an overhead that you | |
539 | don't want in production. | |
540 | ||
d677124b | 541 | |
c903ff83 MT |
542 | config RCU_FANOUT |
543 | int "Tree-based hierarchical RCU fanout value" | |
544 | range 2 64 if 64BIT | |
545 | range 2 32 if !64BIT | |
f41d911f | 546 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
547 | default 64 if 64BIT |
548 | default 32 if !64BIT | |
549 | help | |
550 | This option controls the fanout of hierarchical implementations | |
551 | of RCU, allowing RCU to work efficiently on machines with | |
4d87ffad PM |
552 | large numbers of CPUs. This value must be at least the fourth |
553 | root of NR_CPUS, which allows NR_CPUS to be insanely large. | |
554 | The default value of RCU_FANOUT should be used for production | |
555 | systems, but if you are stress-testing the RCU implementation | |
556 | itself, small RCU_FANOUT values allow you to test large-system | |
557 | code paths on small(er) systems. | |
c903ff83 MT |
558 | |
559 | Select a specific number if testing RCU itself. | |
560 | Take the default if unsure. | |
561 | ||
8932a63d PM |
562 | config RCU_FANOUT_LEAF |
563 | int "Tree-based hierarchical RCU leaf-level fanout value" | |
564 | range 2 RCU_FANOUT if 64BIT | |
565 | range 2 RCU_FANOUT if !64BIT | |
566 | depends on TREE_RCU || TREE_PREEMPT_RCU | |
567 | default 16 | |
568 | help | |
569 | This option controls the leaf-level fanout of hierarchical | |
570 | implementations of RCU, and allows trading off cache misses | |
571 | against lock contention. Systems that synchronize their | |
572 | scheduling-clock interrupts for energy-efficiency reasons will | |
573 | want the default because the smaller leaf-level fanout keeps | |
574 | lock contention levels acceptably low. Very large systems | |
575 | (hundreds or thousands of CPUs) will instead want to set this | |
576 | value to the maximum value possible in order to reduce the | |
577 | number of cache misses incurred during RCU's grace-period | |
578 | initialization. These systems tend to run CPU-bound, and thus | |
579 | are not helped by synchronized interrupts, and thus tend to | |
580 | skew them, which reduces lock contention enough that large | |
581 | leaf-level fanouts work well. | |
582 | ||
583 | Select a specific number if testing RCU itself. | |
584 | ||
585 | Select the maximum permissible value for large systems. | |
586 | ||
587 | Take the default if unsure. | |
588 | ||
c903ff83 MT |
589 | config RCU_FANOUT_EXACT |
590 | bool "Disable tree-based hierarchical RCU auto-balancing" | |
f41d911f | 591 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
592 | default n |
593 | help | |
594 | This option forces use of the exact RCU_FANOUT value specified, | |
595 | regardless of imbalances in the hierarchy. This is useful for | |
596 | testing RCU itself, and might one day be useful on systems with | |
597 | strong NUMA behavior. | |
598 | ||
599 | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. | |
600 | ||
601 | Say N if unsure. | |
602 | ||
8bd93a2c PM |
603 | config RCU_FAST_NO_HZ |
604 | bool "Accelerate last non-dyntick-idle CPU's grace periods" | |
3451d024 | 605 | depends on NO_HZ_COMMON && SMP |
8bd93a2c PM |
606 | default n |
607 | help | |
c0f4dfd4 PM |
608 | This option permits CPUs to enter dynticks-idle state even if |
609 | they have RCU callbacks queued, and prevents RCU from waking | |
610 | these CPUs up more than roughly once every four jiffies (by | |
611 | default, you can adjust this using the rcutree.rcu_idle_gp_delay | |
612 | parameter), thus improving energy efficiency. On the other | |
613 | hand, this option increases the duration of RCU grace periods, | |
614 | for example, slowing down synchronize_rcu(). | |
ba49df47 | 615 | |
c0f4dfd4 PM |
616 | Say Y if energy efficiency is critically important, and you |
617 | don't care about increased grace-period durations. | |
8bd93a2c PM |
618 | |
619 | Say N if you are unsure. | |
620 | ||
c903ff83 | 621 | config TREE_RCU_TRACE |
f41d911f | 622 | def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) |
c903ff83 MT |
623 | select DEBUG_FS |
624 | help | |
f41d911f PM |
625 | This option provides tracing for the TREE_RCU and |
626 | TREE_PREEMPT_RCU implementations, permitting Makefile to | |
627 | trivially select kernel/rcutree_trace.c. | |
c903ff83 | 628 | |
24278d14 PM |
629 | config RCU_BOOST |
630 | bool "Enable RCU priority boosting" | |
27f4d280 | 631 | depends on RT_MUTEXES && PREEMPT_RCU |
24278d14 PM |
632 | default n |
633 | help | |
634 | This option boosts the priority of preempted RCU readers that | |
635 | block the current preemptible RCU grace period for too long. | |
636 | This option also prevents heavy loads from blocking RCU | |
637 | callback invocation for all flavors of RCU. | |
638 | ||
639 | Say Y here if you are working with real-time apps or heavy loads | |
640 | Say N here if you are unsure. | |
641 | ||
642 | config RCU_BOOST_PRIO | |
643 | int "Real-time priority to boost RCU readers to" | |
644 | range 1 99 | |
645 | depends on RCU_BOOST | |
646 | default 1 | |
647 | help | |
c9336643 PM |
648 | This option specifies the real-time priority to which long-term |
649 | preempted RCU readers are to be boosted. If you are working | |
650 | with a real-time application that has one or more CPU-bound | |
651 | threads running at a real-time priority level, you should set | |
652 | RCU_BOOST_PRIO to a priority higher then the highest-priority | |
653 | real-time CPU-bound thread. The default RCU_BOOST_PRIO value | |
654 | of 1 is appropriate in the common case, which is real-time | |
655 | applications that do not have any CPU-bound threads. | |
656 | ||
657 | Some real-time applications might not have a single real-time | |
658 | thread that saturates a given CPU, but instead might have | |
659 | multiple real-time threads that, taken together, fully utilize | |
660 | that CPU. In this case, you should set RCU_BOOST_PRIO to | |
661 | a priority higher than the lowest-priority thread that is | |
662 | conspiring to prevent the CPU from running any non-real-time | |
663 | tasks. For example, if one thread at priority 10 and another | |
664 | thread at priority 5 are between themselves fully consuming | |
665 | the CPU time on a given CPU, then RCU_BOOST_PRIO should be | |
666 | set to priority 6 or higher. | |
24278d14 PM |
667 | |
668 | Specify the real-time priority, or take the default if unsure. | |
669 | ||
670 | config RCU_BOOST_DELAY | |
671 | int "Milliseconds to delay boosting after RCU grace-period start" | |
672 | range 0 3000 | |
673 | depends on RCU_BOOST | |
674 | default 500 | |
675 | help | |
676 | This option specifies the time to wait after the beginning of | |
677 | a given grace period before priority-boosting preempted RCU | |
678 | readers blocking that grace period. Note that any RCU reader | |
679 | blocking an expedited RCU grace period is boosted immediately. | |
680 | ||
681 | Accept the default if unsure. | |
682 | ||
3fbfbf7a | 683 | config RCU_NOCB_CPU |
9a5739d7 | 684 | bool "Offload RCU callback processing from boot-selected CPUs" |
3fbfbf7a PM |
685 | depends on TREE_RCU || TREE_PREEMPT_RCU |
686 | default n | |
687 | help | |
688 | Use this option to reduce OS jitter for aggressive HPC or | |
689 | real-time workloads. It can also be used to offload RCU | |
690 | callback invocation to energy-efficient CPUs in battery-powered | |
691 | asymmetric multiprocessors. | |
692 | ||
693 | This option offloads callback invocation from the set of | |
694 | CPUs specified at boot time by the rcu_nocbs parameter. | |
a4889858 PM |
695 | For each such CPU, a kthread ("rcuox/N") will be created to |
696 | invoke callbacks, where the "N" is the CPU being offloaded, | |
697 | and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and | |
698 | "s" for RCU-sched. Nothing prevents this kthread from running | |
699 | on the specified CPUs, but (1) the kthreads may be preempted | |
700 | between each callback, and (2) affinity or cgroups can be used | |
701 | to force the kthreads to run on whatever set of CPUs is desired. | |
3fbfbf7a | 702 | |
34ed6246 | 703 | Say Y here if you want to help to debug reduced OS jitter. |
3fbfbf7a PM |
704 | Say N here if you are unsure. |
705 | ||
911af505 PM |
706 | choice |
707 | prompt "Build-forced no-CBs CPUs" | |
708 | default RCU_NOCB_CPU_NONE | |
709 | help | |
676c3dc2 PM |
710 | This option allows no-CBs CPUs (whose RCU callbacks are invoked |
711 | from kthreads rather than from softirq context) to be specified | |
712 | at build time. Additional no-CBs CPUs may be specified by | |
713 | the rcu_nocbs= boot parameter. | |
911af505 PM |
714 | |
715 | config RCU_NOCB_CPU_NONE | |
716 | bool "No build_forced no-CBs CPUs" | |
73c30828 | 717 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
911af505 PM |
718 | help |
719 | This option does not force any of the CPUs to be no-CBs CPUs. | |
720 | Only CPUs designated by the rcu_nocbs= boot parameter will be | |
676c3dc2 PM |
721 | no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU |
722 | kthreads whose names begin with "rcuo". All other CPUs will | |
723 | invoke their own RCU callbacks in softirq context. | |
724 | ||
725 | Select this option if you want to choose no-CBs CPUs at | |
726 | boot time, for example, to allow testing of different no-CBs | |
727 | configurations without having to rebuild the kernel each time. | |
911af505 PM |
728 | |
729 | config RCU_NOCB_CPU_ZERO | |
730 | bool "CPU 0 is a build_forced no-CBs CPU" | |
73c30828 | 731 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
911af505 | 732 | help |
676c3dc2 PM |
733 | This option forces CPU 0 to be a no-CBs CPU, so that its RCU |
734 | callbacks are invoked by a per-CPU kthread whose name begins | |
735 | with "rcuo". Additional CPUs may be designated as no-CBs | |
736 | CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs. | |
737 | All other CPUs will invoke their own RCU callbacks in softirq | |
738 | context. | |
911af505 PM |
739 | |
740 | Select this if CPU 0 needs to be a no-CBs CPU for real-time | |
676c3dc2 PM |
741 | or energy-efficiency reasons, but the real reason it exists |
742 | is to ensure that randconfig testing covers mixed systems. | |
911af505 PM |
743 | |
744 | config RCU_NOCB_CPU_ALL | |
745 | bool "All CPUs are build_forced no-CBs CPUs" | |
746 | depends on RCU_NOCB_CPU | |
747 | help | |
748 | This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= | |
676c3dc2 PM |
749 | boot parameter will be ignored. All CPUs' RCU callbacks will |
750 | be executed in the context of per-CPU rcuo kthreads created for | |
751 | this purpose. Assuming that the kthreads whose names start with | |
752 | "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter | |
753 | on the remaining CPUs, but might decrease memory locality during | |
754 | RCU-callback invocation, thus potentially degrading throughput. | |
911af505 PM |
755 | |
756 | Select this if all CPUs need to be no-CBs CPUs for real-time | |
757 | or energy-efficiency reasons. | |
758 | ||
759 | endchoice | |
760 | ||
c903ff83 MT |
761 | endmenu # "RCU Subsystem" |
762 | ||
1da177e4 | 763 | config IKCONFIG |
f2443ab6 | 764 | tristate "Kernel .config support" |
1da177e4 LT |
765 | ---help--- |
766 | This option enables the complete Linux kernel ".config" file | |
767 | contents to be saved in the kernel. It provides documentation | |
768 | of which kernel options are used in a running kernel or in an | |
769 | on-disk kernel. This information can be extracted from the kernel | |
770 | image file with the script scripts/extract-ikconfig and used as | |
771 | input to rebuild the current kernel or to build another kernel. | |
772 | It can also be extracted from a running kernel by reading | |
773 | /proc/config.gz if enabled (below). | |
774 | ||
775 | config IKCONFIG_PROC | |
776 | bool "Enable access to .config through /proc/config.gz" | |
777 | depends on IKCONFIG && PROC_FS | |
778 | ---help--- | |
779 | This option enables access to the kernel configuration file | |
780 | through /proc/config.gz. | |
781 | ||
794543a2 AJS |
782 | config LOG_BUF_SHIFT |
783 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | |
784 | range 12 21 | |
f17a32e9 | 785 | default 17 |
794543a2 AJS |
786 | help |
787 | Select kernel log buffer size as a power of 2. | |
f17a32e9 AB |
788 | Examples: |
789 | 17 => 128 KB | |
790 | 16 => 64 KB | |
791 | 15 => 32 KB | |
792 | 14 => 16 KB | |
794543a2 AJS |
793 | 13 => 8 KB |
794 | 12 => 4 KB | |
795 | ||
a5574cf6 IM |
796 | # |
797 | # Architectures with an unreliable sched_clock() should select this: | |
798 | # | |
799 | config HAVE_UNSTABLE_SCHED_CLOCK | |
800 | bool | |
801 | ||
38ff87f7 SB |
802 | config GENERIC_SCHED_CLOCK |
803 | bool | |
804 | ||
be3a7284 AA |
805 | # |
806 | # For architectures that want to enable the support for NUMA-affine scheduler | |
807 | # balancing logic: | |
808 | # | |
809 | config ARCH_SUPPORTS_NUMA_BALANCING | |
810 | bool | |
811 | ||
be5e610c PZ |
812 | # |
813 | # For architectures that know their GCC __int128 support is sound | |
814 | # | |
815 | config ARCH_SUPPORTS_INT128 | |
816 | bool | |
817 | ||
be3a7284 AA |
818 | # For architectures that (ab)use NUMA to represent different memory regions |
819 | # all cpu-local but of different latencies, such as SuperH. | |
820 | # | |
821 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
822 | bool | |
823 | ||
824 | # | |
825 | # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE | |
826 | config ARCH_WANTS_PROT_NUMA_PROT_NONE | |
827 | bool | |
828 | ||
829 | config ARCH_USES_NUMA_PROT_NONE | |
830 | bool | |
831 | default y | |
832 | depends on ARCH_WANTS_PROT_NUMA_PROT_NONE | |
833 | depends on NUMA_BALANCING | |
834 | ||
1a687c2e MG |
835 | config NUMA_BALANCING_DEFAULT_ENABLED |
836 | bool "Automatically enable NUMA aware memory/task placement" | |
837 | default y | |
838 | depends on NUMA_BALANCING | |
839 | help | |
6d56a410 | 840 | If set, automatic NUMA balancing will be enabled if running on a NUMA |
1a687c2e MG |
841 | machine. |
842 | ||
be3a7284 AA |
843 | config NUMA_BALANCING |
844 | bool "Memory placement aware NUMA scheduler" | |
be3a7284 AA |
845 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
846 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
847 | depends on SMP && NUMA && MIGRATION | |
848 | help | |
849 | This option adds support for automatic NUMA aware memory/task placement. | |
850 | The mechanism is quite primitive and is based on migrating memory when | |
6d56a410 | 851 | it has references to the node the task is running on. |
be3a7284 AA |
852 | |
853 | This system will be inactive on UMA systems. | |
854 | ||
23964d2d LZ |
855 | menuconfig CGROUPS |
856 | boolean "Control Group support" | |
5cdc38f9 | 857 | help |
23964d2d | 858 | This option adds support for grouping sets of processes together, for |
5cdc38f9 KH |
859 | use with process control subsystems such as Cpusets, CFS, memory |
860 | controls or device isolation. | |
861 | See | |
5cdc38f9 | 862 | - Documentation/scheduler/sched-design-CFS.txt (CFS) |
45ce80fb LZ |
863 | - Documentation/cgroups/ (features for grouping, isolation |
864 | and resource control) | |
5cdc38f9 KH |
865 | |
866 | Say N if unsure. | |
867 | ||
23964d2d LZ |
868 | if CGROUPS |
869 | ||
5cdc38f9 KH |
870 | config CGROUP_DEBUG |
871 | bool "Example debug cgroup subsystem" | |
5cdc38f9 KH |
872 | default n |
873 | help | |
874 | This option enables a simple cgroup subsystem that | |
875 | exports useful debugging information about the cgroups | |
23964d2d | 876 | framework. |
5cdc38f9 | 877 | |
23964d2d | 878 | Say N if unsure. |
5cdc38f9 | 879 | |
5cdc38f9 | 880 | config CGROUP_FREEZER |
23964d2d | 881 | bool "Freezer cgroup subsystem" |
23964d2d LZ |
882 | help |
883 | Provides a way to freeze and unfreeze all tasks in a | |
5cdc38f9 KH |
884 | cgroup. |
885 | ||
886 | config CGROUP_DEVICE | |
887 | bool "Device controller for cgroups" | |
5cdc38f9 KH |
888 | help |
889 | Provides a cgroup implementing whitelists for devices which | |
890 | a process in the cgroup can mknod or open. | |
891 | ||
892 | config CPUSETS | |
893 | bool "Cpuset support" | |
5cdc38f9 KH |
894 | help |
895 | This option will let you create and manage CPUSETs which | |
896 | allow dynamically partitioning a system into sets of CPUs and | |
897 | Memory Nodes and assigning tasks to run only within those sets. | |
898 | This is primarily useful on large SMP or NUMA systems. | |
899 | ||
900 | Say N if unsure. | |
901 | ||
23964d2d LZ |
902 | config PROC_PID_CPUSET |
903 | bool "Include legacy /proc/<pid>/cpuset file" | |
904 | depends on CPUSETS | |
905 | default y | |
906 | ||
d842de87 SV |
907 | config CGROUP_CPUACCT |
908 | bool "Simple CPU accounting cgroup subsystem" | |
d842de87 SV |
909 | help |
910 | Provides a simple Resource Controller for monitoring the | |
23964d2d | 911 | total CPU consumed by the tasks in a cgroup. |
d842de87 | 912 | |
e552b661 PE |
913 | config RESOURCE_COUNTERS |
914 | bool "Resource counters" | |
915 | help | |
916 | This option enables controller independent resource accounting | |
23964d2d | 917 | infrastructure that works with cgroups. |
e552b661 | 918 | |
c255a458 | 919 | config MEMCG |
00f0b825 | 920 | bool "Memory Resource Controller for Control Groups" |
79ae9c29 | 921 | depends on RESOURCE_COUNTERS |
cf475ad2 | 922 | select MM_OWNER |
79bd9814 | 923 | select EVENTFD |
00f0b825 | 924 | help |
84ad6d70 | 925 | Provides a memory resource controller that manages both anonymous |
21acb9ca | 926 | memory and page cache. (See Documentation/cgroups/memory.txt) |
00f0b825 BS |
927 | |
928 | Note that setting this option increases fixed memory overhead | |
84ad6d70 | 929 | associated with each page of memory in the system. By this, |
f60e2a96 | 930 | 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory |
84ad6d70 KH |
931 | usage tracking struct at boot. Total amount of this is printed out |
932 | at boot. | |
00f0b825 BS |
933 | |
934 | Only enable when you're ok with these trade offs and really | |
84ad6d70 KH |
935 | sure you need the memory resource controller. Even when you enable |
936 | this, you can set "cgroup_disable=memory" at your boot option to | |
937 | disable memory resource controller and you can avoid overheads. | |
c9d5409f | 938 | (and lose benefits of memory resource controller) |
00f0b825 | 939 | |
cf475ad2 BS |
940 | This config option also selects MM_OWNER config option, which |
941 | could in turn add some fork/exit overhead. | |
942 | ||
c255a458 | 943 | config MEMCG_SWAP |
65e0e811 | 944 | bool "Memory Resource Controller Swap Extension" |
c255a458 | 945 | depends on MEMCG && SWAP |
c077719b KH |
946 | help |
947 | Add swap management feature to memory resource controller. When you | |
948 | enable this, you can limit mem+swap usage per cgroup. In other words, | |
949 | when you disable this, memory resource controller has no cares to | |
950 | usage of swap...a process can exhaust all of the swap. This extension | |
951 | is useful when you want to avoid exhaustion swap but this itself | |
952 | adds more overheads and consumes memory for remembering information. | |
953 | Especially if you use 32bit system or small memory system, please | |
954 | be careful about enabling this. When memory resource controller | |
955 | is disabled by boot option, this will be automatically disabled and | |
956 | there will be no overhead from this. Even when you set this config=y, | |
00a66d29 | 957 | if boot option "swapaccount=0" is set, swap will not be accounted. |
627991a2 KH |
958 | Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page |
959 | size is 4096bytes, 512k per 1Gbytes of swap. | |
c255a458 | 960 | config MEMCG_SWAP_ENABLED |
a42c390c | 961 | bool "Memory Resource Controller Swap Extension enabled by default" |
c255a458 | 962 | depends on MEMCG_SWAP |
a42c390c MH |
963 | default y |
964 | help | |
965 | Memory Resource Controller Swap Extension comes with its price in | |
966 | a bigger memory consumption. General purpose distribution kernels | |
43d547f9 | 967 | which want to enable the feature but keep it disabled by default |
07555ac1 | 968 | and let the user enable it by swapaccount=1 boot command line |
a42c390c MH |
969 | parameter should have this option unselected. |
970 | For those who want to have the feature enabled by default should | |
971 | select this option (if, for some reason, they need to disable it | |
00a66d29 | 972 | then swapaccount=0 does the trick). |
c255a458 | 973 | config MEMCG_KMEM |
19c92399 KC |
974 | bool "Memory Resource Controller Kernel Memory accounting" |
975 | depends on MEMCG | |
510fc4e1 | 976 | depends on SLUB || SLAB |
e5671dfa GC |
977 | help |
978 | The Kernel Memory extension for Memory Resource Controller can limit | |
979 | the amount of memory used by kernel objects in the system. Those are | |
980 | fundamentally different from the entities handled by the standard | |
981 | Memory Controller, which are page-based, and can be swapped. Users of | |
982 | the kmem extension can use it to guarantee that no group of processes | |
983 | will ever exhaust kernel resources alone. | |
c077719b | 984 | |
2bc64a20 AK |
985 | config CGROUP_HUGETLB |
986 | bool "HugeTLB Resource Controller for Control Groups" | |
19c92399 | 987 | depends on RESOURCE_COUNTERS && HUGETLB_PAGE |
2bc64a20 AK |
988 | default n |
989 | help | |
990 | Provides a cgroup Resource Controller for HugeTLB pages. | |
991 | When you enable this, you can put a per cgroup limit on HugeTLB usage. | |
992 | The limit is enforced during page fault. Since HugeTLB doesn't | |
993 | support page reclaim, enforcing the limit at page fault time implies | |
994 | that, the application will get SIGBUS signal if it tries to access | |
995 | HugeTLB pages beyond its limit. This requires the application to know | |
996 | beforehand how much HugeTLB pages it would require for its use. The | |
997 | control group is tracked in the third page lru pointer. This means | |
998 | that we cannot use the controller with huge page less than 3 pages. | |
999 | ||
e5d1367f SE |
1000 | config CGROUP_PERF |
1001 | bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" | |
1002 | depends on PERF_EVENTS && CGROUPS | |
1003 | help | |
1004 | This option extends the per-cpu mode to restrict monitoring to | |
2d0f2520 | 1005 | threads which belong to the cgroup specified and run on the |
e5d1367f SE |
1006 | designated cpu. |
1007 | ||
1008 | Say N if unsure. | |
1009 | ||
7c941438 DG |
1010 | menuconfig CGROUP_SCHED |
1011 | bool "Group CPU scheduler" | |
7c941438 DG |
1012 | default n |
1013 | help | |
1014 | This feature lets CPU scheduler recognize task groups and control CPU | |
1015 | bandwidth allocation to such task groups. It uses cgroups to group | |
1016 | tasks. | |
1017 | ||
1018 | if CGROUP_SCHED | |
1019 | config FAIR_GROUP_SCHED | |
1020 | bool "Group scheduling for SCHED_OTHER" | |
1021 | depends on CGROUP_SCHED | |
1022 | default CGROUP_SCHED | |
1023 | ||
ab84d31e PT |
1024 | config CFS_BANDWIDTH |
1025 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" | |
ab84d31e PT |
1026 | depends on FAIR_GROUP_SCHED |
1027 | default n | |
1028 | help | |
1029 | This option allows users to define CPU bandwidth rates (limits) for | |
1030 | tasks running within the fair group scheduler. Groups with no limit | |
1031 | set are considered to be unconstrained and will run with no | |
1032 | restriction. | |
1033 | See tip/Documentation/scheduler/sched-bwc.txt for more information. | |
1034 | ||
7c941438 DG |
1035 | config RT_GROUP_SCHED |
1036 | bool "Group scheduling for SCHED_RR/FIFO" | |
7c941438 DG |
1037 | depends on CGROUP_SCHED |
1038 | default n | |
1039 | help | |
1040 | This feature lets you explicitly allocate real CPU bandwidth | |
32bd7eb5 | 1041 | to task groups. If enabled, it will also make it impossible to |
7c941438 DG |
1042 | schedule realtime tasks for non-root users until you allocate |
1043 | realtime bandwidth for them. | |
1044 | See Documentation/scheduler/sched-rt-group.txt for more information. | |
1045 | ||
1046 | endif #CGROUP_SCHED | |
1047 | ||
afc24d49 | 1048 | config BLK_CGROUP |
32e380ae | 1049 | bool "Block IO controller" |
79ae9c29 | 1050 | depends on BLOCK |
afc24d49 VG |
1051 | default n |
1052 | ---help--- | |
1053 | Generic block IO controller cgroup interface. This is the common | |
1054 | cgroup interface which should be used by various IO controlling | |
1055 | policies. | |
1056 | ||
1057 | Currently, CFQ IO scheduler uses it to recognize task groups and | |
1058 | control disk bandwidth allocation (proportional time slice allocation) | |
e43473b7 VG |
1059 | to such task groups. It is also used by bio throttling logic in |
1060 | block layer to implement upper limit in IO rates on a device. | |
afc24d49 VG |
1061 | |
1062 | This option only enables generic Block IO controller infrastructure. | |
e43473b7 | 1063 | One needs to also enable actual IO controlling logic/policy. For |
79e2e759 MW |
1064 | enabling proportional weight division of disk bandwidth in CFQ, set |
1065 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set | |
c5e0591a | 1066 | CONFIG_BLK_DEV_THROTTLING=y. |
afc24d49 VG |
1067 | |
1068 | See Documentation/cgroups/blkio-controller.txt for more information. | |
1069 | ||
1070 | config DEBUG_BLK_CGROUP | |
1071 | bool "Enable Block IO controller debugging" | |
1072 | depends on BLK_CGROUP | |
1073 | default n | |
1074 | ---help--- | |
1075 | Enable some debugging help. Currently it exports additional stat | |
1076 | files in a cgroup which can be useful for debugging. | |
1077 | ||
23964d2d | 1078 | endif # CGROUPS |
c077719b | 1079 | |
067bce1a CG |
1080 | config CHECKPOINT_RESTORE |
1081 | bool "Checkpoint/restore support" if EXPERT | |
1082 | default n | |
1083 | help | |
1084 | Enables additional kernel features in a sake of checkpoint/restore. | |
1085 | In particular it adds auxiliary prctl codes to setup process text, | |
1086 | data and heap segment sizes, and a few additional /proc filesystem | |
1087 | entries. | |
1088 | ||
1089 | If unsure, say N here. | |
1090 | ||
8dd2a82c | 1091 | menuconfig NAMESPACES |
6a108a14 DR |
1092 | bool "Namespaces support" if EXPERT |
1093 | default !EXPERT | |
c5289a69 PE |
1094 | help |
1095 | Provides the way to make tasks work with different objects using | |
1096 | the same id. For example same IPC id may refer to different objects | |
1097 | or same user id or pid may refer to different tasks when used in | |
1098 | different namespaces. | |
1099 | ||
8dd2a82c DL |
1100 | if NAMESPACES |
1101 | ||
58bfdd6d PE |
1102 | config UTS_NS |
1103 | bool "UTS namespace" | |
17a6d441 | 1104 | default y |
58bfdd6d PE |
1105 | help |
1106 | In this namespace tasks see different info provided with the | |
1107 | uname() system call | |
1108 | ||
ae5e1b22 PE |
1109 | config IPC_NS |
1110 | bool "IPC namespace" | |
8dd2a82c | 1111 | depends on (SYSVIPC || POSIX_MQUEUE) |
17a6d441 | 1112 | default y |
ae5e1b22 PE |
1113 | help |
1114 | In this namespace tasks work with IPC ids which correspond to | |
614b84cf | 1115 | different IPC objects in different namespaces. |
ae5e1b22 | 1116 | |
aee16ce7 | 1117 | config USER_NS |
19c92399 | 1118 | bool "User namespace" |
5673a94c | 1119 | default n |
aee16ce7 PE |
1120 | help |
1121 | This allows containers, i.e. vservers, to use user namespaces | |
1122 | to provide different user info for different servers. | |
e11f0ae3 EB |
1123 | |
1124 | When user namespaces are enabled in the kernel it is | |
1125 | recommended that the MEMCG and MEMCG_KMEM options also be | |
1126 | enabled and that user-space use the memory control groups to | |
1127 | limit the amount of memory a memory unprivileged users can | |
1128 | use. | |
1129 | ||
aee16ce7 PE |
1130 | If unsure, say N. |
1131 | ||
74bd59bb | 1132 | config PID_NS |
9bd38c2c | 1133 | bool "PID Namespaces" |
17a6d441 | 1134 | default y |
74bd59bb | 1135 | help |
12d2b8f9 | 1136 | Support process id namespaces. This allows having multiple |
692105b8 | 1137 | processes with the same pid as long as they are in different |
74bd59bb PE |
1138 | pid namespaces. This is a building block of containers. |
1139 | ||
d6eb633f MH |
1140 | config NET_NS |
1141 | bool "Network namespace" | |
8dd2a82c | 1142 | depends on NET |
17a6d441 | 1143 | default y |
d6eb633f MH |
1144 | help |
1145 | Allow user space to create what appear to be multiple instances | |
1146 | of the network stack. | |
1147 | ||
8dd2a82c DL |
1148 | endif # NAMESPACES |
1149 | ||
5091faa4 MG |
1150 | config SCHED_AUTOGROUP |
1151 | bool "Automatic process group scheduling" | |
5091faa4 MG |
1152 | select CGROUPS |
1153 | select CGROUP_SCHED | |
1154 | select FAIR_GROUP_SCHED | |
1155 | help | |
1156 | This option optimizes the scheduler for common desktop workloads by | |
1157 | automatically creating and populating task groups. This separation | |
1158 | of workloads isolates aggressive CPU burners (like build jobs) from | |
1159 | desktop applications. Task group autogeneration is currently based | |
1160 | upon task session. | |
1161 | ||
7af37bec DL |
1162 | config MM_OWNER |
1163 | bool | |
1164 | ||
1165 | config SYSFS_DEPRECATED | |
5d6a4ea5 | 1166 | bool "Enable deprecated sysfs features to support old userspace tools" |
7af37bec DL |
1167 | depends on SYSFS |
1168 | default n | |
1169 | help | |
1170 | This option adds code that switches the layout of the "block" class | |
1171 | devices, to not show up in /sys/class/block/, but only in | |
1172 | /sys/block/. | |
1173 | ||
1174 | This switch is only active when the sysfs.deprecated=1 boot option is | |
1175 | passed or the SYSFS_DEPRECATED_V2 option is set. | |
1176 | ||
1177 | This option allows new kernels to run on old distributions and tools, | |
1178 | which might get confused by /sys/class/block/. Since 2007/2008 all | |
1179 | major distributions and tools handle this just fine. | |
1180 | ||
1181 | Recent distributions and userspace tools after 2009/2010 depend on | |
1182 | the existence of /sys/class/block/, and will not work with this | |
1183 | option enabled. | |
1184 | ||
1185 | Only if you are using a new kernel on an old distribution, you might | |
1186 | need to say Y here. | |
1187 | ||
1188 | config SYSFS_DEPRECATED_V2 | |
5d6a4ea5 | 1189 | bool "Enable deprecated sysfs features by default" |
7af37bec DL |
1190 | default n |
1191 | depends on SYSFS | |
1192 | depends on SYSFS_DEPRECATED | |
1193 | help | |
1194 | Enable deprecated sysfs by default. | |
1195 | ||
1196 | See the CONFIG_SYSFS_DEPRECATED option for more details about this | |
1197 | option. | |
1198 | ||
1199 | Only if you are using a new kernel on an old distribution, you might | |
1200 | need to say Y here. Even then, odds are you would not need it | |
1201 | enabled, you can always pass the boot option if absolutely necessary. | |
1202 | ||
1203 | config RELAY | |
1204 | bool "Kernel->user space relay support (formerly relayfs)" | |
1205 | help | |
1206 | This option enables support for relay interface support in | |
1207 | certain file systems (such as debugfs). | |
1208 | It is designed to provide an efficient mechanism for tools and | |
1209 | facilities to relay large amounts of data from kernel space to | |
1210 | user space. | |
1211 | ||
1212 | If unsure, say N. | |
1213 | ||
f991633d DG |
1214 | config BLK_DEV_INITRD |
1215 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | |
1216 | depends on BROKEN || !FRV | |
1217 | help | |
1218 | The initial RAM filesystem is a ramfs which is loaded by the | |
1219 | boot loader (loadlin or lilo) and that is mounted as root | |
1220 | before the normal boot procedure. It is typically used to | |
1221 | load modules needed to mount the "real" root file system, | |
1222 | etc. See <file:Documentation/initrd.txt> for details. | |
1223 | ||
1224 | If RAM disk support (BLK_DEV_RAM) is also included, this | |
1225 | also enables initial RAM disk (initrd) support and adds | |
1226 | 15 Kbytes (more on some other architectures) to the kernel size. | |
1227 | ||
1228 | If unsure say Y. | |
1229 | ||
c33df4ea JPS |
1230 | if BLK_DEV_INITRD |
1231 | ||
dbec4866 SR |
1232 | source "usr/Kconfig" |
1233 | ||
c33df4ea JPS |
1234 | endif |
1235 | ||
c45b4f1f | 1236 | config CC_OPTIMIZE_FOR_SIZE |
96fffeb4 | 1237 | bool "Optimize for size" |
c45b4f1f LT |
1238 | help |
1239 | Enabling this option will pass "-Os" instead of "-O2" to gcc | |
1240 | resulting in a smaller kernel. | |
1241 | ||
3a55fb0d | 1242 | If unsure, say N. |
c45b4f1f | 1243 | |
0847062a RD |
1244 | config SYSCTL |
1245 | bool | |
1246 | ||
b943c460 RD |
1247 | config ANON_INODES |
1248 | bool | |
1249 | ||
657a5209 MF |
1250 | config HAVE_UID16 |
1251 | bool | |
1252 | ||
1253 | config SYSCTL_EXCEPTION_TRACE | |
1254 | bool | |
1255 | help | |
1256 | Enable support for /proc/sys/debug/exception-trace. | |
1257 | ||
1258 | config SYSCTL_ARCH_UNALIGN_NO_WARN | |
1259 | bool | |
1260 | help | |
1261 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap | |
1262 | Allows arch to define/use @no_unaligned_warning to possibly warn | |
1263 | about unaligned access emulation going on under the hood. | |
1264 | ||
1265 | config SYSCTL_ARCH_UNALIGN_ALLOW | |
1266 | bool | |
1267 | help | |
1268 | Enable support for /proc/sys/kernel/unaligned-trap | |
1269 | Allows arches to define/use @unaligned_enabled to runtime toggle | |
1270 | the unaligned access emulation. | |
1271 | see arch/parisc/kernel/unaligned.c for reference | |
1272 | ||
657a5209 MF |
1273 | config HAVE_PCSPKR_PLATFORM |
1274 | bool | |
1275 | ||
6a108a14 DR |
1276 | menuconfig EXPERT |
1277 | bool "Configure standard kernel features (expert users)" | |
f505c553 JT |
1278 | # Unhide debug options, to make the on-by-default options visible |
1279 | select DEBUG_KERNEL | |
1da177e4 LT |
1280 | help |
1281 | This option allows certain base kernel options and settings | |
1282 | to be disabled or tweaked. This is for specialized | |
1283 | environments which can tolerate a "non-standard" kernel. | |
1284 | Only use this if you really know what you are doing. | |
1285 | ||
ae81f9e3 | 1286 | config UID16 |
6a108a14 | 1287 | bool "Enable 16-bit UID system calls" if EXPERT |
af1839eb | 1288 | depends on HAVE_UID16 |
ae81f9e3 CE |
1289 | default y |
1290 | help | |
1291 | This enables the legacy 16-bit UID syscall wrappers. | |
1292 | ||
b89a8171 | 1293 | config SYSCTL_SYSCALL |
6a108a14 | 1294 | bool "Sysctl syscall support" if EXPERT |
26a7034b | 1295 | depends on PROC_SYSCTL |
c736de60 | 1296 | default n |
b89a8171 | 1297 | select SYSCTL |
ae81f9e3 | 1298 | ---help--- |
13bb7e37 EB |
1299 | sys_sysctl uses binary paths that have been found challenging |
1300 | to properly maintain and use. The interface in /proc/sys | |
1301 | using paths with ascii names is now the primary path to this | |
1302 | information. | |
b89a8171 | 1303 | |
13bb7e37 EB |
1304 | Almost nothing using the binary sysctl interface so if you are |
1305 | trying to save some space it is probably safe to disable this, | |
1306 | making your kernel marginally smaller. | |
b89a8171 | 1307 | |
c736de60 | 1308 | If unsure say N here. |
ae81f9e3 | 1309 | |
1da177e4 | 1310 | config KALLSYMS |
6a108a14 | 1311 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
1da177e4 LT |
1312 | default y |
1313 | help | |
1314 | Say Y here to let the kernel print out symbolic crash information and | |
1315 | symbolic stack backtraces. This increases the size of the kernel | |
1316 | somewhat, as all symbols have to be loaded into the kernel image. | |
1317 | ||
1318 | config KALLSYMS_ALL | |
1319 | bool "Include all symbols in kallsyms" | |
1320 | depends on DEBUG_KERNEL && KALLSYMS | |
1321 | help | |
71a83ec7 AB |
1322 | Normally kallsyms only contains the symbols of functions for nicer |
1323 | OOPS messages and backtraces (i.e., symbols from the text and inittext | |
1324 | sections). This is sufficient for most cases. And only in very rare | |
1325 | cases (e.g., when a debugger is used) all symbols are required (e.g., | |
1326 | names of variables from the data sections, etc). | |
1327 | ||
1328 | This option makes sure that all symbols are loaded into the kernel | |
1329 | image (i.e., symbols from all sections) in cost of increased kernel | |
1330 | size (depending on the kernel configuration, it may be 300KiB or | |
1331 | something like this). | |
1332 | ||
1333 | Say N unless you really need all symbols. | |
d59745ce MM |
1334 | |
1335 | config PRINTK | |
1336 | default y | |
6a108a14 | 1337 | bool "Enable support for printk" if EXPERT |
74876a98 | 1338 | select IRQ_WORK |
d59745ce MM |
1339 | help |
1340 | This option enables normal printk support. Removing it | |
1341 | eliminates most of the message strings from the kernel image | |
1342 | and makes the kernel more or less silent. As this makes it | |
1343 | very difficult to diagnose system problems, saying N here is | |
1344 | strongly discouraged. | |
1345 | ||
c8538a7a | 1346 | config BUG |
6a108a14 | 1347 | bool "BUG() support" if EXPERT |
c8538a7a MM |
1348 | default y |
1349 | help | |
1350 | Disabling this option eliminates support for BUG and WARN, reducing | |
1351 | the size of your kernel image and potentially quietly ignoring | |
1352 | numerous fatal conditions. You should only consider disabling this | |
1353 | option for embedded systems with no facilities for reporting errors. | |
1354 | Just say Y. | |
1355 | ||
708e9a79 | 1356 | config ELF_CORE |
046d662f | 1357 | depends on COREDUMP |
708e9a79 | 1358 | default y |
6a108a14 | 1359 | bool "Enable ELF core dumps" if EXPERT |
708e9a79 MM |
1360 | help |
1361 | Enable support for generating core dumps. Disabling saves about 4k. | |
1362 | ||
8761f1ab | 1363 | |
e5e1d3cb | 1364 | config PCSPKR_PLATFORM |
6a108a14 | 1365 | bool "Enable PC-Speaker support" if EXPERT |
8761f1ab | 1366 | depends on HAVE_PCSPKR_PLATFORM |
15f304b6 | 1367 | select I8253_LOCK |
e5e1d3cb SS |
1368 | default y |
1369 | help | |
1370 | This option allows to disable the internal PC-Speaker | |
1371 | support, saving some memory. | |
1372 | ||
1da177e4 LT |
1373 | config BASE_FULL |
1374 | default y | |
6a108a14 | 1375 | bool "Enable full-sized data structures for core" if EXPERT |
1da177e4 LT |
1376 | help |
1377 | Disabling this option reduces the size of miscellaneous core | |
1378 | kernel data structures. This saves memory on small machines, | |
1379 | but may reduce performance. | |
1380 | ||
1381 | config FUTEX | |
6a108a14 | 1382 | bool "Enable futex support" if EXPERT |
1da177e4 | 1383 | default y |
23f78d4a | 1384 | select RT_MUTEXES |
1da177e4 LT |
1385 | help |
1386 | Disabling this option will cause the kernel to be built without | |
1387 | support for "fast userspace mutexes". The resulting kernel may not | |
1388 | run glibc-based applications correctly. | |
1389 | ||
1390 | config EPOLL | |
6a108a14 | 1391 | bool "Enable eventpoll support" if EXPERT |
1da177e4 | 1392 | default y |
448e3cee | 1393 | select ANON_INODES |
1da177e4 LT |
1394 | help |
1395 | Disabling this option will cause the kernel to be built without | |
1396 | support for epoll family of system calls. | |
1397 | ||
fba2afaa | 1398 | config SIGNALFD |
6a108a14 | 1399 | bool "Enable signalfd() system call" if EXPERT |
448e3cee | 1400 | select ANON_INODES |
fba2afaa DL |
1401 | default y |
1402 | help | |
1403 | Enable the signalfd() system call that allows to receive signals | |
1404 | on a file descriptor. | |
1405 | ||
1406 | If unsure, say Y. | |
1407 | ||
b215e283 | 1408 | config TIMERFD |
6a108a14 | 1409 | bool "Enable timerfd() system call" if EXPERT |
448e3cee | 1410 | select ANON_INODES |
b215e283 DL |
1411 | default y |
1412 | help | |
1413 | Enable the timerfd() system call that allows to receive timer | |
1414 | events on a file descriptor. | |
1415 | ||
1416 | If unsure, say Y. | |
1417 | ||
e1ad7468 | 1418 | config EVENTFD |
6a108a14 | 1419 | bool "Enable eventfd() system call" if EXPERT |
448e3cee | 1420 | select ANON_INODES |
e1ad7468 DL |
1421 | default y |
1422 | help | |
1423 | Enable the eventfd() system call that allows to receive both | |
1424 | kernel notification (ie. KAIO) or userspace notifications. | |
1425 | ||
1426 | If unsure, say Y. | |
1427 | ||
1da177e4 | 1428 | config SHMEM |
6a108a14 | 1429 | bool "Use full shmem filesystem" if EXPERT |
1da177e4 LT |
1430 | default y |
1431 | depends on MMU | |
1432 | help | |
1433 | The shmem is an internal filesystem used to manage shared memory. | |
1434 | It is backed by swap and manages resource limits. It is also exported | |
1435 | to userspace as tmpfs if TMPFS is enabled. Disabling this | |
1436 | option replaces shmem and tmpfs with the much simpler ramfs code, | |
1437 | which may be appropriate on small systems without swap. | |
1438 | ||
ebf3f09c | 1439 | config AIO |
6a108a14 | 1440 | bool "Enable AIO support" if EXPERT |
ebf3f09c TP |
1441 | default y |
1442 | help | |
1443 | This option enables POSIX asynchronous I/O which may by used | |
657a5209 MF |
1444 | by some high performance threaded applications. Disabling |
1445 | this option saves about 7k. | |
1446 | ||
1447 | config PCI_QUIRKS | |
1448 | default y | |
1449 | bool "Enable PCI quirk workarounds" if EXPERT | |
1450 | depends on PCI | |
1451 | help | |
1452 | This enables workarounds for various PCI chipset | |
1453 | bugs/quirks. Disable this only if your target machine is | |
1454 | unaffected by PCI quirks. | |
ebf3f09c | 1455 | |
6befe5f6 RD |
1456 | config EMBEDDED |
1457 | bool "Embedded system" | |
1458 | select EXPERT | |
1459 | help | |
1460 | This option should be enabled if compiling the kernel for | |
1461 | an embedded system so certain expert options are available | |
1462 | for configuration. | |
1463 | ||
cdd6c482 | 1464 | config HAVE_PERF_EVENTS |
0793a61d | 1465 | bool |
018df72d MF |
1466 | help |
1467 | See tools/perf/design.txt for details. | |
0793a61d | 1468 | |
906010b2 PZ |
1469 | config PERF_USE_VMALLOC |
1470 | bool | |
1471 | help | |
1472 | See tools/perf/design.txt for details | |
1473 | ||
57c0c15b | 1474 | menu "Kernel Performance Events And Counters" |
0793a61d | 1475 | |
cdd6c482 | 1476 | config PERF_EVENTS |
57c0c15b | 1477 | bool "Kernel performance events and counters" |
392d65a9 | 1478 | default y if PROFILING |
cdd6c482 | 1479 | depends on HAVE_PERF_EVENTS |
4c59e467 | 1480 | select ANON_INODES |
e360adbe | 1481 | select IRQ_WORK |
0793a61d | 1482 | help |
57c0c15b IM |
1483 | Enable kernel support for various performance events provided |
1484 | by software and hardware. | |
0793a61d | 1485 | |
dd77038d | 1486 | Software events are supported either built-in or via the |
57c0c15b | 1487 | use of generic tracepoints. |
0793a61d | 1488 | |
57c0c15b IM |
1489 | Most modern CPUs support performance events via performance |
1490 | counter registers. These registers count the number of certain | |
0793a61d TG |
1491 | types of hw events: such as instructions executed, cachemisses |
1492 | suffered, or branches mis-predicted - without slowing down the | |
1493 | kernel or applications. These registers can also trigger interrupts | |
1494 | when a threshold number of events have passed - and can thus be | |
1495 | used to profile the code that runs on that CPU. | |
1496 | ||
57c0c15b | 1497 | The Linux Performance Event subsystem provides an abstraction of |
dd77038d | 1498 | these software and hardware event capabilities, available via a |
57c0c15b | 1499 | system call and used by the "perf" utility in tools/perf/. It |
0793a61d TG |
1500 | provides per task and per CPU counters, and it provides event |
1501 | capabilities on top of those. | |
1502 | ||
1503 | Say Y if unsure. | |
1504 | ||
906010b2 PZ |
1505 | config DEBUG_PERF_USE_VMALLOC |
1506 | default n | |
1507 | bool "Debug: use vmalloc to back perf mmap() buffers" | |
1508 | depends on PERF_EVENTS && DEBUG_KERNEL | |
1509 | select PERF_USE_VMALLOC | |
1510 | help | |
1511 | Use vmalloc memory to back perf mmap() buffers. | |
1512 | ||
1513 | Mostly useful for debugging the vmalloc code on platforms | |
1514 | that don't require it. | |
1515 | ||
1516 | Say N if unsure. | |
1517 | ||
0793a61d TG |
1518 | endmenu |
1519 | ||
f8891e5e CL |
1520 | config VM_EVENT_COUNTERS |
1521 | default y | |
6a108a14 | 1522 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
f8891e5e | 1523 | help |
2aea4fb6 PJ |
1524 | VM event counters are needed for event counts to be shown. |
1525 | This option allows the disabling of the VM event counters | |
6a108a14 | 1526 | on EXPERT systems. /proc/vmstat will only show page counts |
2aea4fb6 | 1527 | if VM event counters are disabled. |
f8891e5e | 1528 | |
41ecc55b CL |
1529 | config SLUB_DEBUG |
1530 | default y | |
6a108a14 | 1531 | bool "Enable SLUB debugging support" if EXPERT |
f6acb635 | 1532 | depends on SLUB && SYSFS |
41ecc55b CL |
1533 | help |
1534 | SLUB has extensive debug support features. Disabling these can | |
1535 | result in significant savings in code size. This also disables | |
1536 | SLUB sysfs support. /sys/slab will not exist and there will be | |
1537 | no support for cache validation etc. | |
1538 | ||
b943c460 RD |
1539 | config COMPAT_BRK |
1540 | bool "Disable heap randomization" | |
1541 | default y | |
1542 | help | |
1543 | Randomizing heap placement makes heap exploits harder, but it | |
1544 | also breaks ancient binaries (including anything libc5 based). | |
1545 | This option changes the bootup default to heap randomization | |
692105b8 | 1546 | disabled, and can be overridden at runtime by setting |
b943c460 RD |
1547 | /proc/sys/kernel/randomize_va_space to 2. |
1548 | ||
1549 | On non-ancient distros (post-2000 ones) N is usually a safe choice. | |
1550 | ||
81819f0f CL |
1551 | choice |
1552 | prompt "Choose SLAB allocator" | |
a0acd820 | 1553 | default SLUB |
81819f0f CL |
1554 | help |
1555 | This option allows to select a slab allocator. | |
1556 | ||
1557 | config SLAB | |
1558 | bool "SLAB" | |
1559 | help | |
1560 | The regular slab allocator that is established and known to work | |
34013886 | 1561 | well in all environments. It organizes cache hot objects in |
02f56210 | 1562 | per cpu and per node queues. |
81819f0f CL |
1563 | |
1564 | config SLUB | |
81819f0f CL |
1565 | bool "SLUB (Unqueued Allocator)" |
1566 | help | |
1567 | SLUB is a slab allocator that minimizes cache line usage | |
1568 | instead of managing queues of cached objects (SLAB approach). | |
1569 | Per cpu caching is realized using slabs of objects instead | |
1570 | of queues of objects. SLUB can use memory efficiently | |
02f56210 SA |
1571 | and has enhanced diagnostics. SLUB is the default choice for |
1572 | a slab allocator. | |
81819f0f CL |
1573 | |
1574 | config SLOB | |
6a108a14 | 1575 | depends on EXPERT |
81819f0f CL |
1576 | bool "SLOB (Simple Allocator)" |
1577 | help | |
37291458 MM |
1578 | SLOB replaces the stock allocator with a drastically simpler |
1579 | allocator. SLOB is generally more space efficient but | |
1580 | does not perform as well on large systems. | |
81819f0f CL |
1581 | |
1582 | endchoice | |
1583 | ||
345c905d JK |
1584 | config SLUB_CPU_PARTIAL |
1585 | default y | |
b39ffbf8 | 1586 | depends on SLUB && SMP |
345c905d JK |
1587 | bool "SLUB per cpu partial cache" |
1588 | help | |
1589 | Per cpu partial caches accellerate objects allocation and freeing | |
1590 | that is local to a processor at the price of more indeterminism | |
1591 | in the latency of the free. On overflow these caches will be cleared | |
1592 | which requires the taking of locks that may cause latency spikes. | |
1593 | Typically one would choose no for a realtime system. | |
1594 | ||
ea637639 JZ |
1595 | config MMAP_ALLOW_UNINITIALIZED |
1596 | bool "Allow mmapped anonymous memory to be uninitialized" | |
6a108a14 | 1597 | depends on EXPERT && !MMU |
ea637639 JZ |
1598 | default n |
1599 | help | |
1600 | Normally, and according to the Linux spec, anonymous memory obtained | |
1601 | from mmap() has it's contents cleared before it is passed to | |
1602 | userspace. Enabling this config option allows you to request that | |
1603 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus | |
1604 | providing a huge performance boost. If this option is not enabled, | |
1605 | then the flag will be ignored. | |
1606 | ||
1607 | This is taken advantage of by uClibc's malloc(), and also by | |
1608 | ELF-FDPIC binfmt's brk and stack allocator. | |
1609 | ||
1610 | Because of the obvious security issues, this option should only be | |
1611 | enabled on embedded devices where you control what is run in | |
1612 | userspace. Since that isn't generally a problem on no-MMU systems, | |
1613 | it is normally safe to say Y here. | |
1614 | ||
1615 | See Documentation/nommu-mmap.txt for more information. | |
1616 | ||
125e5645 | 1617 | config PROFILING |
b309a294 | 1618 | bool "Profiling support" |
125e5645 MD |
1619 | help |
1620 | Say Y here to enable the extended profiling support mechanisms used | |
1621 | by profilers such as OProfile. | |
1622 | ||
5f87f112 IM |
1623 | # |
1624 | # Place an empty function call at each tracepoint site. Can be | |
1625 | # dynamically changed for a probe function. | |
1626 | # | |
97e1c18e | 1627 | config TRACEPOINTS |
5f87f112 | 1628 | bool |
97e1c18e | 1629 | |
fb32e03f MD |
1630 | source "arch/Kconfig" |
1631 | ||
1da177e4 LT |
1632 | endmenu # General setup |
1633 | ||
ee7e5516 DB |
1634 | config HAVE_GENERIC_DMA_COHERENT |
1635 | bool | |
1636 | default n | |
1637 | ||
158a9624 LT |
1638 | config SLABINFO |
1639 | bool | |
1640 | depends on PROC_FS | |
0f389ec6 | 1641 | depends on SLAB || SLUB_DEBUG |
158a9624 LT |
1642 | default y |
1643 | ||
ae81f9e3 CE |
1644 | config RT_MUTEXES |
1645 | boolean | |
ae81f9e3 | 1646 | |
1da177e4 LT |
1647 | config BASE_SMALL |
1648 | int | |
1649 | default 0 if BASE_FULL | |
1650 | default 1 if !BASE_FULL | |
1651 | ||
b56e5a17 DH |
1652 | config SYSTEM_TRUSTED_KEYRING |
1653 | bool "Provide system-wide ring of trusted keys" | |
1654 | depends on KEYS | |
1655 | help | |
1656 | Provide a system keyring to which trusted keys can be added. Keys in | |
1657 | the keyring are considered to be trusted. Keys may be added at will | |
1658 | by the kernel from compiled-in data and from hardware key stores, but | |
1659 | userspace may only add extra keys if those keys can be verified by | |
1660 | keys already in the keyring. | |
1661 | ||
1662 | Keys in this keyring are used by module signature checking. | |
1663 | ||
66da5733 | 1664 | menuconfig MODULES |
1da177e4 | 1665 | bool "Enable loadable module support" |
11097a03 | 1666 | option modules |
1da177e4 LT |
1667 | help |
1668 | Kernel modules are small pieces of compiled code which can | |
1669 | be inserted in the running kernel, rather than being | |
1670 | permanently built into the kernel. You use the "modprobe" | |
1671 | tool to add (and sometimes remove) them. If you say Y here, | |
1672 | many parts of the kernel can be built as modules (by | |
1673 | answering M instead of Y where indicated): this is most | |
1674 | useful for infrequently used options which are not required | |
1675 | for booting. For more information, see the man pages for | |
1676 | modprobe, lsmod, modinfo, insmod and rmmod. | |
1677 | ||
1678 | If you say Y here, you will need to run "make | |
1679 | modules_install" to put the modules under /lib/modules/ | |
1680 | where modprobe can find them (you may need to be root to do | |
1681 | this). | |
1682 | ||
1683 | If unsure, say Y. | |
1684 | ||
0b0de144 RD |
1685 | if MODULES |
1686 | ||
826e4506 LT |
1687 | config MODULE_FORCE_LOAD |
1688 | bool "Forced module loading" | |
826e4506 LT |
1689 | default n |
1690 | help | |
91e37a79 RR |
1691 | Allow loading of modules without version information (ie. modprobe |
1692 | --force). Forced module loading sets the 'F' (forced) taint flag and | |
1693 | is usually a really bad idea. | |
826e4506 | 1694 | |
1da177e4 LT |
1695 | config MODULE_UNLOAD |
1696 | bool "Module unloading" | |
1da177e4 LT |
1697 | help |
1698 | Without this option you will not be able to unload any | |
1699 | modules (note that some modules may not be unloadable | |
f7f5b675 DV |
1700 | anyway), which makes your kernel smaller, faster |
1701 | and simpler. If unsure, say Y. | |
1da177e4 LT |
1702 | |
1703 | config MODULE_FORCE_UNLOAD | |
1704 | bool "Forced module unloading" | |
19c92399 | 1705 | depends on MODULE_UNLOAD |
1da177e4 LT |
1706 | help |
1707 | This option allows you to force a module to unload, even if the | |
1708 | kernel believes it is unsafe: the kernel will remove the module | |
1709 | without waiting for anyone to stop using it (using the -f option to | |
1710 | rmmod). This is mainly for kernel developers and desperate users. | |
1711 | If unsure, say N. | |
1712 | ||
1da177e4 | 1713 | config MODVERSIONS |
0d541643 | 1714 | bool "Module versioning support" |
1da177e4 LT |
1715 | help |
1716 | Usually, you have to use modules compiled with your kernel. | |
1717 | Saying Y here makes it sometimes possible to use modules | |
1718 | compiled for different kernels, by adding enough information | |
1719 | to the modules to (hopefully) spot any changes which would | |
1720 | make them incompatible with the kernel you are running. If | |
1721 | unsure, say N. | |
1722 | ||
1723 | config MODULE_SRCVERSION_ALL | |
1724 | bool "Source checksum for all modules" | |
1da177e4 LT |
1725 | help |
1726 | Modules which contain a MODULE_VERSION get an extra "srcversion" | |
1727 | field inserted into their modinfo section, which contains a | |
1728 | sum of the source files which made it. This helps maintainers | |
1729 | see exactly which source was used to build a module (since | |
1730 | others sometimes change the module source without updating | |
1731 | the version). With this option, such a "srcversion" field | |
1732 | will be created for all modules. If unsure, say N. | |
1733 | ||
106a4ee2 RR |
1734 | config MODULE_SIG |
1735 | bool "Module signature verification" | |
1736 | depends on MODULES | |
b56e5a17 | 1737 | select SYSTEM_TRUSTED_KEYRING |
48ba2462 DH |
1738 | select KEYS |
1739 | select CRYPTO | |
1740 | select ASYMMETRIC_KEY_TYPE | |
1741 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE | |
1742 | select PUBLIC_KEY_ALGO_RSA | |
1743 | select ASN1 | |
1744 | select OID_REGISTRY | |
1745 | select X509_CERTIFICATE_PARSER | |
106a4ee2 RR |
1746 | help |
1747 | Check modules for valid signatures upon load: the signature | |
1748 | is simply appended to the module. For more information see | |
1749 | Documentation/module-signing.txt. | |
1750 | ||
ea0b6dcf DH |
1751 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
1752 | module DOES NOT get stripped after being signed. This includes the | |
1753 | debuginfo strip done by some packagers (such as rpmbuild) and | |
1754 | inclusion into an initramfs that wants the module size reduced. | |
1755 | ||
106a4ee2 RR |
1756 | config MODULE_SIG_FORCE |
1757 | bool "Require modules to be validly signed" | |
1758 | depends on MODULE_SIG | |
1759 | help | |
1760 | Reject unsigned modules or signed modules for which we don't have a | |
1761 | key. Without this, such modules will simply taint the kernel. | |
ea0b6dcf | 1762 | |
d9d8d7ed MM |
1763 | config MODULE_SIG_ALL |
1764 | bool "Automatically sign all modules" | |
1765 | default y | |
1766 | depends on MODULE_SIG | |
1767 | help | |
1768 | Sign all modules during make modules_install. Without this option, | |
1769 | modules must be signed manually, using the scripts/sign-file tool. | |
1770 | ||
1771 | comment "Do not forget to sign required modules with scripts/sign-file" | |
1772 | depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL | |
1773 | ||
ea0b6dcf DH |
1774 | choice |
1775 | prompt "Which hash algorithm should modules be signed with?" | |
1776 | depends on MODULE_SIG | |
1777 | help | |
1778 | This determines which sort of hashing algorithm will be used during | |
1779 | signature generation. This algorithm _must_ be built into the kernel | |
1780 | directly so that signature verification can take place. It is not | |
1781 | possible to load a signed module containing the algorithm to check | |
1782 | the signature on that module. | |
1783 | ||
1784 | config MODULE_SIG_SHA1 | |
1785 | bool "Sign modules with SHA-1" | |
1786 | select CRYPTO_SHA1 | |
1787 | ||
1788 | config MODULE_SIG_SHA224 | |
1789 | bool "Sign modules with SHA-224" | |
1790 | select CRYPTO_SHA256 | |
1791 | ||
1792 | config MODULE_SIG_SHA256 | |
1793 | bool "Sign modules with SHA-256" | |
1794 | select CRYPTO_SHA256 | |
1795 | ||
1796 | config MODULE_SIG_SHA384 | |
1797 | bool "Sign modules with SHA-384" | |
1798 | select CRYPTO_SHA512 | |
1799 | ||
1800 | config MODULE_SIG_SHA512 | |
1801 | bool "Sign modules with SHA-512" | |
1802 | select CRYPTO_SHA512 | |
1803 | ||
1804 | endchoice | |
1805 | ||
22753674 MM |
1806 | config MODULE_SIG_HASH |
1807 | string | |
1808 | depends on MODULE_SIG | |
1809 | default "sha1" if MODULE_SIG_SHA1 | |
1810 | default "sha224" if MODULE_SIG_SHA224 | |
1811 | default "sha256" if MODULE_SIG_SHA256 | |
1812 | default "sha384" if MODULE_SIG_SHA384 | |
1813 | default "sha512" if MODULE_SIG_SHA512 | |
1814 | ||
0b0de144 RD |
1815 | endif # MODULES |
1816 | ||
98a79d6a RR |
1817 | config INIT_ALL_POSSIBLE |
1818 | bool | |
1819 | help | |
5f054e31 RR |
1820 | Back when each arch used to define their own cpu_online_mask and |
1821 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask | |
98a79d6a RR |
1822 | with all 1s, and others with all 0s. When they were centralised, |
1823 | it was better to provide this option than to break all the archs | |
692105b8 | 1824 | and have several arch maintainers pursuing me down dark alleys. |
98a79d6a | 1825 | |
1da177e4 LT |
1826 | config STOP_MACHINE |
1827 | bool | |
1828 | default y | |
1829 | depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU | |
1830 | help | |
1831 | Need stop_machine() primitive. | |
3a65dfe8 | 1832 | |
3a65dfe8 | 1833 | source "block/Kconfig" |
e98c3202 AK |
1834 | |
1835 | config PREEMPT_NOTIFIERS | |
1836 | bool | |
e260be67 | 1837 | |
16295bec SK |
1838 | config PADATA |
1839 | depends on SMP | |
1840 | bool | |
1841 | ||
754b7b63 AK |
1842 | # Can be selected by architectures with broken toolchains |
1843 | # that get confused by correct const<->read_only section | |
1844 | # mappings | |
1845 | config BROKEN_RODATA | |
1846 | bool | |
1847 | ||
4520c6a4 DH |
1848 | config ASN1 |
1849 | tristate | |
1850 | help | |
1851 | Build a simple ASN.1 grammar compiler that produces a bytecode output | |
1852 | that can be interpreted by the ASN.1 stream decoder and used to | |
1853 | inform it as to what tags are to be expected in a stream and what | |
1854 | functions to call on what tags. | |
1855 | ||
6beb0009 | 1856 | source "kernel/Kconfig.locks" |