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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 | ||
226b4ccd KK |
264 | config CROSS_MEMORY_ATTACH |
265 | bool "Enable process_vm_readv/writev syscalls" | |
266 | depends on MMU | |
267 | default y | |
268 | help | |
269 | Enabling this option adds the system calls process_vm_readv and | |
270 | process_vm_writev which allow a process with the correct privileges | |
a2a368d9 | 271 | to directly read from or write to another process' address space. |
226b4ccd KK |
272 | See the man page for more details. |
273 | ||
391dc69c FW |
274 | config FHANDLE |
275 | bool "open by fhandle syscalls" | |
276 | select EXPORTFS | |
277 | help | |
278 | If you say Y here, a user level program will be able to map | |
279 | file names to handle and then later use the handle for | |
280 | different file system operations. This is useful in implementing | |
281 | userspace file servers, which now track files using handles instead | |
282 | of names. The handle would remain the same even if file names | |
283 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) | |
284 | syscalls. | |
285 | ||
69369a70 JT |
286 | config USELIB |
287 | bool "uselib syscall" | |
b2113a41 | 288 | def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION |
69369a70 JT |
289 | help |
290 | This option enables the uselib syscall, a system call used in the | |
291 | dynamic linker from libc5 and earlier. glibc does not use this | |
292 | system call. If you intend to run programs built on libc5 or | |
293 | earlier, you may need to enable this syscall. Current systems | |
294 | running glibc can safely disable this. | |
295 | ||
391dc69c FW |
296 | config AUDIT |
297 | bool "Auditing support" | |
298 | depends on NET | |
299 | help | |
300 | Enable auditing infrastructure that can be used with another | |
301 | kernel subsystem, such as SELinux (which requires this for | |
cb74ed27 PM |
302 | logging of avc messages output). System call auditing is included |
303 | on architectures which support it. | |
391dc69c | 304 | |
7a017721 AT |
305 | config HAVE_ARCH_AUDITSYSCALL |
306 | bool | |
307 | ||
391dc69c | 308 | config AUDITSYSCALL |
cb74ed27 | 309 | def_bool y |
7a017721 | 310 | depends on AUDIT && HAVE_ARCH_AUDITSYSCALL |
391dc69c FW |
311 | |
312 | config AUDIT_WATCH | |
313 | def_bool y | |
314 | depends on AUDITSYSCALL | |
315 | select FSNOTIFY | |
316 | ||
317 | config AUDIT_TREE | |
318 | def_bool y | |
319 | depends on AUDITSYSCALL | |
320 | select FSNOTIFY | |
321 | ||
391dc69c FW |
322 | source "kernel/irq/Kconfig" |
323 | source "kernel/time/Kconfig" | |
324 | ||
325 | menu "CPU/Task time and stats accounting" | |
326 | ||
abf917cd FW |
327 | config VIRT_CPU_ACCOUNTING |
328 | bool | |
329 | ||
fdf9c356 FW |
330 | choice |
331 | prompt "Cputime accounting" | |
332 | default TICK_CPU_ACCOUNTING if !PPC64 | |
02fc8d37 | 333 | default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
fdf9c356 FW |
334 | |
335 | # Kind of a stub config for the pure tick based cputime accounting | |
336 | config TICK_CPU_ACCOUNTING | |
337 | bool "Simple tick based cputime accounting" | |
c58b0df1 | 338 | depends on !S390 && !NO_HZ_FULL |
fdf9c356 FW |
339 | help |
340 | This is the basic tick based cputime accounting that maintains | |
341 | statistics about user, system and idle time spent on per jiffies | |
342 | granularity. | |
343 | ||
344 | If unsure, say Y. | |
345 | ||
abf917cd | 346 | config VIRT_CPU_ACCOUNTING_NATIVE |
b952741c | 347 | bool "Deterministic task and CPU time accounting" |
c58b0df1 | 348 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
abf917cd | 349 | select VIRT_CPU_ACCOUNTING |
b952741c FW |
350 | help |
351 | Select this option to enable more accurate task and CPU time | |
352 | accounting. This is done by reading a CPU counter on each | |
353 | kernel entry and exit and on transitions within the kernel | |
354 | between system, softirq and hardirq state, so there is a | |
355 | small performance impact. In the case of s390 or IBM POWER > 5, | |
356 | this also enables accounting of stolen time on logically-partitioned | |
357 | systems. | |
358 | ||
abf917cd FW |
359 | config VIRT_CPU_ACCOUNTING_GEN |
360 | bool "Full dynticks CPU time accounting" | |
ff3fb254 | 361 | depends on HAVE_CONTEXT_TRACKING |
554b0004 | 362 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
abf917cd FW |
363 | select VIRT_CPU_ACCOUNTING |
364 | select CONTEXT_TRACKING | |
365 | help | |
366 | Select this option to enable task and CPU time accounting on full | |
367 | dynticks systems. This accounting is implemented by watching every | |
368 | kernel-user boundaries using the context tracking subsystem. | |
369 | The accounting is thus performed at the expense of some significant | |
370 | overhead. | |
371 | ||
372 | For now this is only useful if you are working on the full | |
373 | dynticks subsystem development. | |
374 | ||
375 | If unsure, say N. | |
376 | ||
fdf9c356 FW |
377 | config IRQ_TIME_ACCOUNTING |
378 | bool "Fine granularity task level IRQ time accounting" | |
c58b0df1 | 379 | depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL |
fdf9c356 FW |
380 | help |
381 | Select this option to enable fine granularity task irq time | |
382 | accounting. This is done by reading a timestamp on each | |
383 | transitions between softirq and hardirq state, so there can be a | |
384 | small performance impact. | |
385 | ||
386 | If in doubt, say N here. | |
387 | ||
388 | endchoice | |
389 | ||
1da177e4 LT |
390 | config BSD_PROCESS_ACCT |
391 | bool "BSD Process Accounting" | |
2813893f | 392 | depends on MULTIUSER |
1da177e4 LT |
393 | help |
394 | If you say Y here, a user level program will be able to instruct the | |
395 | kernel (via a special system call) to write process accounting | |
396 | information to a file: whenever a process exits, information about | |
397 | that process will be appended to the file by the kernel. The | |
398 | information includes things such as creation time, owning user, | |
399 | command name, memory usage, controlling terminal etc. (the complete | |
400 | list is in the struct acct in <file:include/linux/acct.h>). It is | |
401 | up to the user level program to do useful things with this | |
402 | information. This is generally a good idea, so say Y. | |
403 | ||
404 | config BSD_PROCESS_ACCT_V3 | |
405 | bool "BSD Process Accounting version 3 file format" | |
406 | depends on BSD_PROCESS_ACCT | |
407 | default n | |
408 | help | |
409 | If you say Y here, the process accounting information is written | |
410 | in a new file format that also logs the process IDs of each | |
411 | process and it's parent. Note that this file format is incompatible | |
412 | with previous v0/v1/v2 file formats, so you will need updated tools | |
413 | for processing it. A preliminary version of these tools is available | |
37a4c940 | 414 | at <http://www.gnu.org/software/acct/>. |
1da177e4 | 415 | |
c757249a | 416 | config TASKSTATS |
19c92399 | 417 | bool "Export task/process statistics through netlink" |
c757249a | 418 | depends on NET |
2813893f | 419 | depends on MULTIUSER |
c757249a SN |
420 | default n |
421 | help | |
422 | Export selected statistics for tasks/processes through the | |
423 | generic netlink interface. Unlike BSD process accounting, the | |
424 | statistics are available during the lifetime of tasks/processes as | |
425 | responses to commands. Like BSD accounting, they are sent to user | |
426 | space on task exit. | |
427 | ||
428 | Say N if unsure. | |
429 | ||
ca74e92b | 430 | config TASK_DELAY_ACCT |
19c92399 | 431 | bool "Enable per-task delay accounting" |
6f44993f | 432 | depends on TASKSTATS |
f6db8347 | 433 | select SCHED_INFO |
ca74e92b SN |
434 | help |
435 | Collect information on time spent by a task waiting for system | |
436 | resources like cpu, synchronous block I/O completion and swapping | |
437 | in pages. Such statistics can help in setting a task's priorities | |
438 | relative to other tasks for cpu, io, rss limits etc. | |
439 | ||
440 | Say N if unsure. | |
441 | ||
18f705f4 | 442 | config TASK_XACCT |
19c92399 | 443 | bool "Enable extended accounting over taskstats" |
18f705f4 AD |
444 | depends on TASKSTATS |
445 | help | |
446 | Collect extended task accounting data and send the data | |
447 | to userland for processing over the taskstats interface. | |
448 | ||
449 | Say N if unsure. | |
450 | ||
451 | config TASK_IO_ACCOUNTING | |
19c92399 | 452 | bool "Enable per-task storage I/O accounting" |
18f705f4 AD |
453 | depends on TASK_XACCT |
454 | help | |
455 | Collect information on the number of bytes of storage I/O which this | |
456 | task has caused. | |
457 | ||
458 | Say N if unsure. | |
459 | ||
391dc69c | 460 | endmenu # "CPU/Task time and stats accounting" |
d9817ebe | 461 | |
c903ff83 MT |
462 | menu "RCU Subsystem" |
463 | ||
c903ff83 | 464 | config TREE_RCU |
e72aeafc PK |
465 | bool |
466 | default y if !PREEMPT && SMP | |
c903ff83 MT |
467 | help |
468 | This option selects the RCU implementation that is | |
469 | designed for very large SMP system with hundreds or | |
c17ef453 PM |
470 | thousands of CPUs. It also scales down nicely to |
471 | smaller systems. | |
c903ff83 | 472 | |
28f6569a | 473 | config PREEMPT_RCU |
e72aeafc PK |
474 | bool |
475 | default y if PREEMPT | |
f41d911f PM |
476 | help |
477 | This option selects the RCU implementation that is | |
478 | designed for very large SMP systems with hundreds or | |
479 | thousands of CPUs, but for which real-time response | |
bbe3eae8 PM |
480 | is also required. It also scales down nicely to |
481 | smaller systems. | |
f41d911f | 482 | |
9fc52d83 PM |
483 | Select this option if you are unsure. |
484 | ||
9b1d82fa | 485 | config TINY_RCU |
e72aeafc PK |
486 | bool |
487 | default y if !PREEMPT && !SMP | |
9b1d82fa PM |
488 | help |
489 | This option selects the RCU implementation that is | |
490 | designed for UP systems from which real-time response | |
491 | is not required. This option greatly reduces the | |
492 | memory footprint of RCU. | |
493 | ||
78cae10b PM |
494 | config RCU_EXPERT |
495 | bool "Make expert-level adjustments to RCU configuration" | |
496 | default n | |
497 | help | |
498 | This option needs to be enabled if you wish to make | |
499 | expert-level adjustments to RCU configuration. By default, | |
500 | no such adjustments can be made, which has the often-beneficial | |
501 | side-effect of preventing "make oldconfig" from asking you all | |
502 | sorts of detailed questions about how you would like numerous | |
503 | obscure RCU options to be set up. | |
504 | ||
505 | Say Y if you need to make expert-level adjustments to RCU. | |
506 | ||
507 | Say N if you are unsure. | |
508 | ||
83fe27ea PK |
509 | config SRCU |
510 | bool | |
511 | help | |
512 | This option selects the sleepable version of RCU. This version | |
513 | permits arbitrary sleeping or blocking within RCU read-side critical | |
514 | sections. | |
515 | ||
8315f422 | 516 | config TASKS_RCU |
82d0f4c0 | 517 | bool |
8315f422 | 518 | default n |
83fe27ea | 519 | select SRCU |
8315f422 PM |
520 | help |
521 | This option enables a task-based RCU implementation that uses | |
522 | only voluntary context switch (not preemption!), idle, and | |
523 | user-mode execution as quiescent states. | |
524 | ||
6bfc09e2 | 525 | config RCU_STALL_COMMON |
28f6569a | 526 | def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE ) |
6bfc09e2 PM |
527 | help |
528 | This option enables RCU CPU stall code that is common between | |
529 | the TINY and TREE variants of RCU. The purpose is to allow | |
530 | the tiny variants to disable RCU CPU stall warnings, while | |
531 | making these warnings mandatory for the tree variants. | |
532 | ||
91d1aa43 FW |
533 | config CONTEXT_TRACKING |
534 | bool | |
535 | ||
91d1aa43 FW |
536 | config CONTEXT_TRACKING_FORCE |
537 | bool "Force context tracking" | |
538 | depends on CONTEXT_TRACKING | |
d84d27a4 | 539 | default y if !NO_HZ_FULL |
1fd2b442 | 540 | help |
d84d27a4 FW |
541 | The major pre-requirement for full dynticks to work is to |
542 | support the context tracking subsystem. But there are also | |
543 | other dependencies to provide in order to make the full | |
544 | dynticks working. | |
545 | ||
546 | This option stands for testing when an arch implements the | |
547 | context tracking backend but doesn't yet fullfill all the | |
548 | requirements to make the full dynticks feature working. | |
549 | Without the full dynticks, there is no way to test the support | |
550 | for context tracking and the subsystems that rely on it: RCU | |
551 | userspace extended quiescent state and tickless cputime | |
552 | accounting. This option copes with the absence of the full | |
553 | dynticks subsystem by forcing the context tracking on all | |
554 | CPUs in the system. | |
555 | ||
99c8b1ea | 556 | Say Y only if you're working on the development of an |
d84d27a4 FW |
557 | architecture backend for the context tracking. |
558 | ||
559 | Say N otherwise, this option brings an overhead that you | |
560 | don't want in production. | |
561 | ||
d677124b | 562 | |
c903ff83 MT |
563 | config RCU_FANOUT |
564 | int "Tree-based hierarchical RCU fanout value" | |
565 | range 2 64 if 64BIT | |
566 | range 2 32 if !64BIT | |
05c5df31 | 567 | depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT |
c903ff83 MT |
568 | default 64 if 64BIT |
569 | default 32 if !64BIT | |
570 | help | |
571 | This option controls the fanout of hierarchical implementations | |
572 | of RCU, allowing RCU to work efficiently on machines with | |
4d87ffad PM |
573 | large numbers of CPUs. This value must be at least the fourth |
574 | root of NR_CPUS, which allows NR_CPUS to be insanely large. | |
575 | The default value of RCU_FANOUT should be used for production | |
576 | systems, but if you are stress-testing the RCU implementation | |
577 | itself, small RCU_FANOUT values allow you to test large-system | |
578 | code paths on small(er) systems. | |
c903ff83 MT |
579 | |
580 | Select a specific number if testing RCU itself. | |
581 | Take the default if unsure. | |
582 | ||
8932a63d PM |
583 | config RCU_FANOUT_LEAF |
584 | int "Tree-based hierarchical RCU leaf-level fanout value" | |
8739c5cb PM |
585 | range 2 64 if 64BIT |
586 | range 2 32 if !64BIT | |
47d631af | 587 | depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT |
8932a63d PM |
588 | default 16 |
589 | help | |
590 | This option controls the leaf-level fanout of hierarchical | |
591 | implementations of RCU, and allows trading off cache misses | |
592 | against lock contention. Systems that synchronize their | |
593 | scheduling-clock interrupts for energy-efficiency reasons will | |
594 | want the default because the smaller leaf-level fanout keeps | |
595 | lock contention levels acceptably low. Very large systems | |
596 | (hundreds or thousands of CPUs) will instead want to set this | |
597 | value to the maximum value possible in order to reduce the | |
598 | number of cache misses incurred during RCU's grace-period | |
599 | initialization. These systems tend to run CPU-bound, and thus | |
600 | are not helped by synchronized interrupts, and thus tend to | |
601 | skew them, which reduces lock contention enough that large | |
602 | leaf-level fanouts work well. | |
603 | ||
604 | Select a specific number if testing RCU itself. | |
605 | ||
606 | Select the maximum permissible value for large systems. | |
607 | ||
608 | Take the default if unsure. | |
609 | ||
8bd93a2c PM |
610 | config RCU_FAST_NO_HZ |
611 | bool "Accelerate last non-dyntick-idle CPU's grace periods" | |
78cae10b | 612 | depends on NO_HZ_COMMON && SMP && RCU_EXPERT |
8bd93a2c PM |
613 | default n |
614 | help | |
c0f4dfd4 PM |
615 | This option permits CPUs to enter dynticks-idle state even if |
616 | they have RCU callbacks queued, and prevents RCU from waking | |
617 | these CPUs up more than roughly once every four jiffies (by | |
618 | default, you can adjust this using the rcutree.rcu_idle_gp_delay | |
619 | parameter), thus improving energy efficiency. On the other | |
620 | hand, this option increases the duration of RCU grace periods, | |
621 | for example, slowing down synchronize_rcu(). | |
ba49df47 | 622 | |
c0f4dfd4 PM |
623 | Say Y if energy efficiency is critically important, and you |
624 | don't care about increased grace-period durations. | |
8bd93a2c PM |
625 | |
626 | Say N if you are unsure. | |
627 | ||
c903ff83 | 628 | config TREE_RCU_TRACE |
28f6569a | 629 | def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU ) |
c903ff83 MT |
630 | select DEBUG_FS |
631 | help | |
f41d911f | 632 | This option provides tracing for the TREE_RCU and |
28f6569a | 633 | PREEMPT_RCU implementations, permitting Makefile to |
f41d911f | 634 | trivially select kernel/rcutree_trace.c. |
c903ff83 | 635 | |
24278d14 PM |
636 | config RCU_BOOST |
637 | bool "Enable RCU priority boosting" | |
78cae10b | 638 | depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT |
24278d14 PM |
639 | default n |
640 | help | |
641 | This option boosts the priority of preempted RCU readers that | |
642 | block the current preemptible RCU grace period for too long. | |
643 | This option also prevents heavy loads from blocking RCU | |
644 | callback invocation for all flavors of RCU. | |
645 | ||
646 | Say Y here if you are working with real-time apps or heavy loads | |
647 | Say N here if you are unsure. | |
648 | ||
21871d7e CW |
649 | config RCU_KTHREAD_PRIO |
650 | int "Real-time priority to use for RCU worker threads" | |
a94844b2 PM |
651 | range 1 99 if RCU_BOOST |
652 | range 0 99 if !RCU_BOOST | |
653 | default 1 if RCU_BOOST | |
654 | default 0 if !RCU_BOOST | |
26730f55 | 655 | depends on RCU_EXPERT |
24278d14 | 656 | help |
21871d7e CW |
657 | This option specifies the SCHED_FIFO priority value that will be |
658 | assigned to the rcuc/n and rcub/n threads and is also the value | |
659 | used for RCU_BOOST (if enabled). If you are working with a | |
660 | real-time application that has one or more CPU-bound threads | |
661 | running at a real-time priority level, you should set | |
662 | RCU_KTHREAD_PRIO to a priority higher than the highest-priority | |
663 | real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO | |
664 | value of 1 is appropriate in the common case, which is real-time | |
c9336643 PM |
665 | applications that do not have any CPU-bound threads. |
666 | ||
667 | Some real-time applications might not have a single real-time | |
668 | thread that saturates a given CPU, but instead might have | |
669 | multiple real-time threads that, taken together, fully utilize | |
21871d7e | 670 | that CPU. In this case, you should set RCU_KTHREAD_PRIO to |
c9336643 PM |
671 | a priority higher than the lowest-priority thread that is |
672 | conspiring to prevent the CPU from running any non-real-time | |
673 | tasks. For example, if one thread at priority 10 and another | |
674 | thread at priority 5 are between themselves fully consuming | |
21871d7e | 675 | the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be |
c9336643 | 676 | set to priority 6 or higher. |
24278d14 PM |
677 | |
678 | Specify the real-time priority, or take the default if unsure. | |
679 | ||
680 | config RCU_BOOST_DELAY | |
681 | int "Milliseconds to delay boosting after RCU grace-period start" | |
682 | range 0 3000 | |
683 | depends on RCU_BOOST | |
684 | default 500 | |
685 | help | |
686 | This option specifies the time to wait after the beginning of | |
687 | a given grace period before priority-boosting preempted RCU | |
688 | readers blocking that grace period. Note that any RCU reader | |
689 | blocking an expedited RCU grace period is boosted immediately. | |
690 | ||
691 | Accept the default if unsure. | |
692 | ||
3fbfbf7a | 693 | config RCU_NOCB_CPU |
9a5739d7 | 694 | bool "Offload RCU callback processing from boot-selected CPUs" |
28f6569a | 695 | depends on TREE_RCU || PREEMPT_RCU |
be55fa2a | 696 | depends on RCU_EXPERT || NO_HZ_FULL |
3fbfbf7a PM |
697 | default n |
698 | help | |
699 | Use this option to reduce OS jitter for aggressive HPC or | |
700 | real-time workloads. It can also be used to offload RCU | |
701 | callback invocation to energy-efficient CPUs in battery-powered | |
702 | asymmetric multiprocessors. | |
703 | ||
704 | This option offloads callback invocation from the set of | |
705 | CPUs specified at boot time by the rcu_nocbs parameter. | |
a4889858 PM |
706 | For each such CPU, a kthread ("rcuox/N") will be created to |
707 | invoke callbacks, where the "N" is the CPU being offloaded, | |
708 | and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and | |
709 | "s" for RCU-sched. Nothing prevents this kthread from running | |
710 | on the specified CPUs, but (1) the kthreads may be preempted | |
711 | between each callback, and (2) affinity or cgroups can be used | |
712 | to force the kthreads to run on whatever set of CPUs is desired. | |
3fbfbf7a | 713 | |
34ed6246 | 714 | Say Y here if you want to help to debug reduced OS jitter. |
3fbfbf7a PM |
715 | Say N here if you are unsure. |
716 | ||
911af505 PM |
717 | choice |
718 | prompt "Build-forced no-CBs CPUs" | |
719 | default RCU_NOCB_CPU_NONE | |
4568779f | 720 | depends on RCU_NOCB_CPU |
911af505 | 721 | help |
676c3dc2 PM |
722 | This option allows no-CBs CPUs (whose RCU callbacks are invoked |
723 | from kthreads rather than from softirq context) to be specified | |
724 | at build time. Additional no-CBs CPUs may be specified by | |
725 | the rcu_nocbs= boot parameter. | |
911af505 PM |
726 | |
727 | config RCU_NOCB_CPU_NONE | |
728 | bool "No build_forced no-CBs CPUs" | |
911af505 PM |
729 | help |
730 | This option does not force any of the CPUs to be no-CBs CPUs. | |
731 | Only CPUs designated by the rcu_nocbs= boot parameter will be | |
676c3dc2 PM |
732 | no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU |
733 | kthreads whose names begin with "rcuo". All other CPUs will | |
734 | invoke their own RCU callbacks in softirq context. | |
735 | ||
736 | Select this option if you want to choose no-CBs CPUs at | |
737 | boot time, for example, to allow testing of different no-CBs | |
738 | configurations without having to rebuild the kernel each time. | |
911af505 PM |
739 | |
740 | config RCU_NOCB_CPU_ZERO | |
741 | bool "CPU 0 is a build_forced no-CBs CPU" | |
911af505 | 742 | help |
676c3dc2 PM |
743 | This option forces CPU 0 to be a no-CBs CPU, so that its RCU |
744 | callbacks are invoked by a per-CPU kthread whose name begins | |
745 | with "rcuo". Additional CPUs may be designated as no-CBs | |
746 | CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs. | |
747 | All other CPUs will invoke their own RCU callbacks in softirq | |
748 | context. | |
911af505 PM |
749 | |
750 | Select this if CPU 0 needs to be a no-CBs CPU for real-time | |
676c3dc2 PM |
751 | or energy-efficiency reasons, but the real reason it exists |
752 | is to ensure that randconfig testing covers mixed systems. | |
911af505 PM |
753 | |
754 | config RCU_NOCB_CPU_ALL | |
755 | bool "All CPUs are build_forced no-CBs CPUs" | |
911af505 PM |
756 | help |
757 | This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= | |
676c3dc2 PM |
758 | boot parameter will be ignored. All CPUs' RCU callbacks will |
759 | be executed in the context of per-CPU rcuo kthreads created for | |
760 | this purpose. Assuming that the kthreads whose names start with | |
761 | "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter | |
762 | on the remaining CPUs, but might decrease memory locality during | |
763 | RCU-callback invocation, thus potentially degrading throughput. | |
911af505 PM |
764 | |
765 | Select this if all CPUs need to be no-CBs CPUs for real-time | |
766 | or energy-efficiency reasons. | |
767 | ||
768 | endchoice | |
769 | ||
ee42571f PM |
770 | config RCU_EXPEDITE_BOOT |
771 | bool | |
772 | default n | |
773 | help | |
774 | This option enables expedited grace periods at boot time, | |
775 | as if rcu_expedite_gp() had been invoked early in boot. | |
776 | The corresponding rcu_unexpedite_gp() is invoked from | |
777 | rcu_end_inkernel_boot(), which is intended to be invoked | |
778 | at the end of the kernel-only boot sequence, just before | |
779 | init is exec'ed. | |
780 | ||
781 | Accept the default if unsure. | |
782 | ||
c903ff83 MT |
783 | endmenu # "RCU Subsystem" |
784 | ||
de5b56ba VG |
785 | config BUILD_BIN2C |
786 | bool | |
787 | default n | |
788 | ||
1da177e4 | 789 | config IKCONFIG |
f2443ab6 | 790 | tristate "Kernel .config support" |
de5b56ba | 791 | select BUILD_BIN2C |
1da177e4 LT |
792 | ---help--- |
793 | This option enables the complete Linux kernel ".config" file | |
794 | contents to be saved in the kernel. It provides documentation | |
795 | of which kernel options are used in a running kernel or in an | |
796 | on-disk kernel. This information can be extracted from the kernel | |
797 | image file with the script scripts/extract-ikconfig and used as | |
798 | input to rebuild the current kernel or to build another kernel. | |
799 | It can also be extracted from a running kernel by reading | |
800 | /proc/config.gz if enabled (below). | |
801 | ||
802 | config IKCONFIG_PROC | |
803 | bool "Enable access to .config through /proc/config.gz" | |
804 | depends on IKCONFIG && PROC_FS | |
805 | ---help--- | |
806 | This option enables access to the kernel configuration file | |
807 | through /proc/config.gz. | |
808 | ||
794543a2 AJS |
809 | config LOG_BUF_SHIFT |
810 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | |
fb39f98d | 811 | range 12 25 |
f17a32e9 | 812 | default 17 |
361e9dfb | 813 | depends on PRINTK |
794543a2 | 814 | help |
23b2899f LR |
815 | Select the minimal kernel log buffer size as a power of 2. |
816 | The final size is affected by LOG_CPU_MAX_BUF_SHIFT config | |
817 | parameter, see below. Any higher size also might be forced | |
818 | by "log_buf_len" boot parameter. | |
819 | ||
f17a32e9 | 820 | Examples: |
23b2899f | 821 | 17 => 128 KB |
f17a32e9 | 822 | 16 => 64 KB |
23b2899f LR |
823 | 15 => 32 KB |
824 | 14 => 16 KB | |
794543a2 AJS |
825 | 13 => 8 KB |
826 | 12 => 4 KB | |
827 | ||
23b2899f LR |
828 | config LOG_CPU_MAX_BUF_SHIFT |
829 | int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" | |
2240a31d | 830 | depends on SMP |
23b2899f LR |
831 | range 0 21 |
832 | default 12 if !BASE_SMALL | |
833 | default 0 if BASE_SMALL | |
361e9dfb | 834 | depends on PRINTK |
23b2899f LR |
835 | help |
836 | This option allows to increase the default ring buffer size | |
837 | according to the number of CPUs. The value defines the contribution | |
838 | of each CPU as a power of 2. The used space is typically only few | |
839 | lines however it might be much more when problems are reported, | |
840 | e.g. backtraces. | |
841 | ||
842 | The increased size means that a new buffer has to be allocated and | |
843 | the original static one is unused. It makes sense only on systems | |
844 | with more CPUs. Therefore this value is used only when the sum of | |
845 | contributions is greater than the half of the default kernel ring | |
846 | buffer as defined by LOG_BUF_SHIFT. The default values are set | |
847 | so that more than 64 CPUs are needed to trigger the allocation. | |
848 | ||
849 | Also this option is ignored when "log_buf_len" kernel parameter is | |
850 | used as it forces an exact (power of two) size of the ring buffer. | |
851 | ||
852 | The number of possible CPUs is used for this computation ignoring | |
853 | hotplugging making the compuation optimal for the the worst case | |
854 | scenerio while allowing a simple algorithm to be used from bootup. | |
855 | ||
856 | Examples shift values and their meaning: | |
857 | 17 => 128 KB for each CPU | |
858 | 16 => 64 KB for each CPU | |
859 | 15 => 32 KB for each CPU | |
860 | 14 => 16 KB for each CPU | |
861 | 13 => 8 KB for each CPU | |
862 | 12 => 4 KB for each CPU | |
863 | ||
a5574cf6 IM |
864 | # |
865 | # Architectures with an unreliable sched_clock() should select this: | |
866 | # | |
867 | config HAVE_UNSTABLE_SCHED_CLOCK | |
868 | bool | |
869 | ||
38ff87f7 SB |
870 | config GENERIC_SCHED_CLOCK |
871 | bool | |
872 | ||
be3a7284 AA |
873 | # |
874 | # For architectures that want to enable the support for NUMA-affine scheduler | |
875 | # balancing logic: | |
876 | # | |
877 | config ARCH_SUPPORTS_NUMA_BALANCING | |
878 | bool | |
879 | ||
72b252ae MG |
880 | # |
881 | # For architectures that prefer to flush all TLBs after a number of pages | |
882 | # are unmapped instead of sending one IPI per page to flush. The architecture | |
883 | # must provide guarantees on what happens if a clean TLB cache entry is | |
884 | # written after the unmap. Details are in mm/rmap.c near the check for | |
885 | # should_defer_flush. The architecture should also consider if the full flush | |
886 | # and the refill costs are offset by the savings of sending fewer IPIs. | |
887 | config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH | |
888 | bool | |
889 | ||
be5e610c PZ |
890 | # |
891 | # For architectures that know their GCC __int128 support is sound | |
892 | # | |
893 | config ARCH_SUPPORTS_INT128 | |
894 | bool | |
895 | ||
be3a7284 AA |
896 | # For architectures that (ab)use NUMA to represent different memory regions |
897 | # all cpu-local but of different latencies, such as SuperH. | |
898 | # | |
899 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
900 | bool | |
901 | ||
be3a7284 AA |
902 | config NUMA_BALANCING |
903 | bool "Memory placement aware NUMA scheduler" | |
be3a7284 AA |
904 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
905 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
906 | depends on SMP && NUMA && MIGRATION | |
907 | help | |
908 | This option adds support for automatic NUMA aware memory/task placement. | |
909 | The mechanism is quite primitive and is based on migrating memory when | |
6d56a410 | 910 | it has references to the node the task is running on. |
be3a7284 AA |
911 | |
912 | This system will be inactive on UMA systems. | |
913 | ||
6f7c97e8 AK |
914 | config NUMA_BALANCING_DEFAULT_ENABLED |
915 | bool "Automatically enable NUMA aware memory/task placement" | |
916 | default y | |
917 | depends on NUMA_BALANCING | |
918 | help | |
919 | If set, automatic NUMA balancing will be enabled if running on a NUMA | |
920 | machine. | |
921 | ||
23964d2d | 922 | menuconfig CGROUPS |
6341e62b | 923 | bool "Control Group support" |
2bd59d48 | 924 | select KERNFS |
5cdc38f9 | 925 | help |
23964d2d | 926 | This option adds support for grouping sets of processes together, for |
5cdc38f9 KH |
927 | use with process control subsystems such as Cpusets, CFS, memory |
928 | controls or device isolation. | |
929 | See | |
5cdc38f9 | 930 | - Documentation/scheduler/sched-design-CFS.txt (CFS) |
45ce80fb LZ |
931 | - Documentation/cgroups/ (features for grouping, isolation |
932 | and resource control) | |
5cdc38f9 KH |
933 | |
934 | Say N if unsure. | |
935 | ||
23964d2d LZ |
936 | if CGROUPS |
937 | ||
3e32cb2e JW |
938 | config PAGE_COUNTER |
939 | bool | |
940 | ||
c255a458 | 941 | config MEMCG |
a0166ec4 | 942 | bool "Memory controller" |
3e32cb2e | 943 | select PAGE_COUNTER |
79bd9814 | 944 | select EVENTFD |
00f0b825 | 945 | help |
a0166ec4 | 946 | Provides control over the memory footprint of tasks in a cgroup. |
00f0b825 | 947 | |
c255a458 | 948 | config MEMCG_SWAP |
a0166ec4 | 949 | bool "Swap controller" |
c255a458 | 950 | depends on MEMCG && SWAP |
c077719b | 951 | help |
a0166ec4 JW |
952 | Provides control over the swap space consumed by tasks in a cgroup. |
953 | ||
c255a458 | 954 | config MEMCG_SWAP_ENABLED |
a0166ec4 | 955 | bool "Swap controller enabled by default" |
c255a458 | 956 | depends on MEMCG_SWAP |
a42c390c MH |
957 | default y |
958 | help | |
959 | Memory Resource Controller Swap Extension comes with its price in | |
960 | a bigger memory consumption. General purpose distribution kernels | |
43d547f9 | 961 | which want to enable the feature but keep it disabled by default |
07555ac1 | 962 | and let the user enable it by swapaccount=1 boot command line |
a42c390c MH |
963 | parameter should have this option unselected. |
964 | For those who want to have the feature enabled by default should | |
965 | select this option (if, for some reason, they need to disable it | |
00a66d29 | 966 | then swapaccount=0 does the trick). |
c077719b | 967 | |
6bf024e6 JW |
968 | config BLK_CGROUP |
969 | bool "IO controller" | |
970 | depends on BLOCK | |
2bc64a20 | 971 | default n |
6bf024e6 JW |
972 | ---help--- |
973 | Generic block IO controller cgroup interface. This is the common | |
974 | cgroup interface which should be used by various IO controlling | |
975 | policies. | |
2bc64a20 | 976 | |
6bf024e6 JW |
977 | Currently, CFQ IO scheduler uses it to recognize task groups and |
978 | control disk bandwidth allocation (proportional time slice allocation) | |
979 | to such task groups. It is also used by bio throttling logic in | |
980 | block layer to implement upper limit in IO rates on a device. | |
e5d1367f | 981 | |
6bf024e6 JW |
982 | This option only enables generic Block IO controller infrastructure. |
983 | One needs to also enable actual IO controlling logic/policy. For | |
984 | enabling proportional weight division of disk bandwidth in CFQ, set | |
985 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set | |
986 | CONFIG_BLK_DEV_THROTTLING=y. | |
987 | ||
988 | See Documentation/cgroups/blkio-controller.txt for more information. | |
989 | ||
990 | config DEBUG_BLK_CGROUP | |
991 | bool "IO controller debugging" | |
992 | depends on BLK_CGROUP | |
993 | default n | |
994 | ---help--- | |
995 | Enable some debugging help. Currently it exports additional stat | |
996 | files in a cgroup which can be useful for debugging. | |
997 | ||
998 | config CGROUP_WRITEBACK | |
999 | bool | |
1000 | depends on MEMCG && BLK_CGROUP | |
1001 | default y | |
e5d1367f | 1002 | |
7c941438 | 1003 | menuconfig CGROUP_SCHED |
a0166ec4 | 1004 | bool "CPU controller" |
7c941438 DG |
1005 | default n |
1006 | help | |
1007 | This feature lets CPU scheduler recognize task groups and control CPU | |
1008 | bandwidth allocation to such task groups. It uses cgroups to group | |
1009 | tasks. | |
1010 | ||
1011 | if CGROUP_SCHED | |
1012 | config FAIR_GROUP_SCHED | |
1013 | bool "Group scheduling for SCHED_OTHER" | |
1014 | depends on CGROUP_SCHED | |
1015 | default CGROUP_SCHED | |
1016 | ||
ab84d31e PT |
1017 | config CFS_BANDWIDTH |
1018 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" | |
ab84d31e PT |
1019 | depends on FAIR_GROUP_SCHED |
1020 | default n | |
1021 | help | |
1022 | This option allows users to define CPU bandwidth rates (limits) for | |
1023 | tasks running within the fair group scheduler. Groups with no limit | |
1024 | set are considered to be unconstrained and will run with no | |
1025 | restriction. | |
1026 | See tip/Documentation/scheduler/sched-bwc.txt for more information. | |
1027 | ||
7c941438 DG |
1028 | config RT_GROUP_SCHED |
1029 | bool "Group scheduling for SCHED_RR/FIFO" | |
7c941438 DG |
1030 | depends on CGROUP_SCHED |
1031 | default n | |
1032 | help | |
1033 | This feature lets you explicitly allocate real CPU bandwidth | |
32bd7eb5 | 1034 | to task groups. If enabled, it will also make it impossible to |
7c941438 DG |
1035 | schedule realtime tasks for non-root users until you allocate |
1036 | realtime bandwidth for them. | |
1037 | See Documentation/scheduler/sched-rt-group.txt for more information. | |
1038 | ||
1039 | endif #CGROUP_SCHED | |
1040 | ||
6bf024e6 JW |
1041 | config CGROUP_PIDS |
1042 | bool "PIDs controller" | |
1043 | help | |
1044 | Provides enforcement of process number limits in the scope of a | |
1045 | cgroup. Any attempt to fork more processes than is allowed in the | |
1046 | cgroup will fail. PIDs are fundamentally a global resource because it | |
1047 | is fairly trivial to reach PID exhaustion before you reach even a | |
1048 | conservative kmemcg limit. As a result, it is possible to grind a | |
1049 | system to halt without being limited by other cgroup policies. The | |
1050 | PIDs cgroup subsystem is designed to stop this from happening. | |
1051 | ||
1052 | It should be noted that organisational operations (such as attaching | |
1053 | to a cgroup hierarchy will *not* be blocked by the PIDs subsystem), | |
1054 | since the PIDs limit only affects a process's ability to fork, not to | |
1055 | attach to a cgroup. | |
1056 | ||
1057 | config CGROUP_FREEZER | |
1058 | bool "Freezer controller" | |
1059 | help | |
1060 | Provides a way to freeze and unfreeze all tasks in a | |
1061 | cgroup. | |
1062 | ||
489c2a20 JW |
1063 | This option affects the ORIGINAL cgroup interface. The cgroup2 memory |
1064 | controller includes important in-kernel memory consumers per default. | |
1065 | ||
1066 | If you're using cgroup2, say N. | |
1067 | ||
6bf024e6 JW |
1068 | config CGROUP_HUGETLB |
1069 | bool "HugeTLB controller" | |
1070 | depends on HUGETLB_PAGE | |
1071 | select PAGE_COUNTER | |
afc24d49 | 1072 | default n |
6bf024e6 JW |
1073 | help |
1074 | Provides a cgroup controller for HugeTLB pages. | |
1075 | When you enable this, you can put a per cgroup limit on HugeTLB usage. | |
1076 | The limit is enforced during page fault. Since HugeTLB doesn't | |
1077 | support page reclaim, enforcing the limit at page fault time implies | |
1078 | that, the application will get SIGBUS signal if it tries to access | |
1079 | HugeTLB pages beyond its limit. This requires the application to know | |
1080 | beforehand how much HugeTLB pages it would require for its use. The | |
1081 | control group is tracked in the third page lru pointer. This means | |
1082 | that we cannot use the controller with huge page less than 3 pages. | |
afc24d49 | 1083 | |
6bf024e6 JW |
1084 | config CPUSETS |
1085 | bool "Cpuset controller" | |
1086 | help | |
1087 | This option will let you create and manage CPUSETs which | |
1088 | allow dynamically partitioning a system into sets of CPUs and | |
1089 | Memory Nodes and assigning tasks to run only within those sets. | |
1090 | This is primarily useful on large SMP or NUMA systems. | |
afc24d49 | 1091 | |
6bf024e6 | 1092 | Say N if unsure. |
afc24d49 | 1093 | |
6bf024e6 JW |
1094 | config PROC_PID_CPUSET |
1095 | bool "Include legacy /proc/<pid>/cpuset file" | |
1096 | depends on CPUSETS | |
1097 | default y | |
afc24d49 | 1098 | |
6bf024e6 JW |
1099 | config CGROUP_DEVICE |
1100 | bool "Device controller" | |
1101 | help | |
1102 | Provides a cgroup controller implementing whitelists for | |
1103 | devices which a process in the cgroup can mknod or open. | |
1104 | ||
1105 | config CGROUP_CPUACCT | |
1106 | bool "Simple CPU accounting controller" | |
1107 | help | |
1108 | Provides a simple controller for monitoring the | |
1109 | total CPU consumed by the tasks in a cgroup. | |
1110 | ||
1111 | config CGROUP_PERF | |
1112 | bool "Perf controller" | |
1113 | depends on PERF_EVENTS | |
1114 | help | |
1115 | This option extends the perf per-cpu mode to restrict monitoring | |
1116 | to threads which belong to the cgroup specified and run on the | |
1117 | designated cpu. | |
1118 | ||
1119 | Say N if unsure. | |
1120 | ||
1121 | config CGROUP_DEBUG | |
1122 | bool "Example controller" | |
afc24d49 | 1123 | default n |
6bf024e6 JW |
1124 | help |
1125 | This option enables a simple controller that exports | |
1126 | debugging information about the cgroups framework. | |
afc24d49 | 1127 | |
6bf024e6 | 1128 | Say N. |
89e9b9e0 | 1129 | |
23964d2d | 1130 | endif # CGROUPS |
c077719b | 1131 | |
067bce1a CG |
1132 | config CHECKPOINT_RESTORE |
1133 | bool "Checkpoint/restore support" if EXPERT | |
2e13ba54 | 1134 | select PROC_CHILDREN |
067bce1a CG |
1135 | default n |
1136 | help | |
1137 | Enables additional kernel features in a sake of checkpoint/restore. | |
1138 | In particular it adds auxiliary prctl codes to setup process text, | |
1139 | data and heap segment sizes, and a few additional /proc filesystem | |
1140 | entries. | |
1141 | ||
1142 | If unsure, say N here. | |
1143 | ||
8dd2a82c | 1144 | menuconfig NAMESPACES |
6a108a14 | 1145 | bool "Namespaces support" if EXPERT |
2813893f | 1146 | depends on MULTIUSER |
6a108a14 | 1147 | default !EXPERT |
c5289a69 PE |
1148 | help |
1149 | Provides the way to make tasks work with different objects using | |
1150 | the same id. For example same IPC id may refer to different objects | |
1151 | or same user id or pid may refer to different tasks when used in | |
1152 | different namespaces. | |
1153 | ||
8dd2a82c DL |
1154 | if NAMESPACES |
1155 | ||
58bfdd6d PE |
1156 | config UTS_NS |
1157 | bool "UTS namespace" | |
17a6d441 | 1158 | default y |
58bfdd6d PE |
1159 | help |
1160 | In this namespace tasks see different info provided with the | |
1161 | uname() system call | |
1162 | ||
ae5e1b22 PE |
1163 | config IPC_NS |
1164 | bool "IPC namespace" | |
8dd2a82c | 1165 | depends on (SYSVIPC || POSIX_MQUEUE) |
17a6d441 | 1166 | default y |
ae5e1b22 PE |
1167 | help |
1168 | In this namespace tasks work with IPC ids which correspond to | |
614b84cf | 1169 | different IPC objects in different namespaces. |
ae5e1b22 | 1170 | |
aee16ce7 | 1171 | config USER_NS |
19c92399 | 1172 | bool "User namespace" |
5673a94c | 1173 | default n |
aee16ce7 PE |
1174 | help |
1175 | This allows containers, i.e. vservers, to use user namespaces | |
1176 | to provide different user info for different servers. | |
e11f0ae3 EB |
1177 | |
1178 | When user namespaces are enabled in the kernel it is | |
d886f4e4 JW |
1179 | recommended that the MEMCG option also be enabled and that |
1180 | user-space use the memory control groups to limit the amount | |
1181 | of memory a memory unprivileged users can use. | |
e11f0ae3 | 1182 | |
aee16ce7 PE |
1183 | If unsure, say N. |
1184 | ||
74bd59bb | 1185 | config PID_NS |
9bd38c2c | 1186 | bool "PID Namespaces" |
17a6d441 | 1187 | default y |
74bd59bb | 1188 | help |
12d2b8f9 | 1189 | Support process id namespaces. This allows having multiple |
692105b8 | 1190 | processes with the same pid as long as they are in different |
74bd59bb PE |
1191 | pid namespaces. This is a building block of containers. |
1192 | ||
d6eb633f MH |
1193 | config NET_NS |
1194 | bool "Network namespace" | |
8dd2a82c | 1195 | depends on NET |
17a6d441 | 1196 | default y |
d6eb633f MH |
1197 | help |
1198 | Allow user space to create what appear to be multiple instances | |
1199 | of the network stack. | |
1200 | ||
8dd2a82c DL |
1201 | endif # NAMESPACES |
1202 | ||
5091faa4 MG |
1203 | config SCHED_AUTOGROUP |
1204 | bool "Automatic process group scheduling" | |
5091faa4 MG |
1205 | select CGROUPS |
1206 | select CGROUP_SCHED | |
1207 | select FAIR_GROUP_SCHED | |
1208 | help | |
1209 | This option optimizes the scheduler for common desktop workloads by | |
1210 | automatically creating and populating task groups. This separation | |
1211 | of workloads isolates aggressive CPU burners (like build jobs) from | |
1212 | desktop applications. Task group autogeneration is currently based | |
1213 | upon task session. | |
1214 | ||
7af37bec | 1215 | config SYSFS_DEPRECATED |
5d6a4ea5 | 1216 | bool "Enable deprecated sysfs features to support old userspace tools" |
7af37bec DL |
1217 | depends on SYSFS |
1218 | default n | |
1219 | help | |
1220 | This option adds code that switches the layout of the "block" class | |
1221 | devices, to not show up in /sys/class/block/, but only in | |
1222 | /sys/block/. | |
1223 | ||
1224 | This switch is only active when the sysfs.deprecated=1 boot option is | |
1225 | passed or the SYSFS_DEPRECATED_V2 option is set. | |
1226 | ||
1227 | This option allows new kernels to run on old distributions and tools, | |
1228 | which might get confused by /sys/class/block/. Since 2007/2008 all | |
1229 | major distributions and tools handle this just fine. | |
1230 | ||
1231 | Recent distributions and userspace tools after 2009/2010 depend on | |
1232 | the existence of /sys/class/block/, and will not work with this | |
1233 | option enabled. | |
1234 | ||
1235 | Only if you are using a new kernel on an old distribution, you might | |
1236 | need to say Y here. | |
1237 | ||
1238 | config SYSFS_DEPRECATED_V2 | |
5d6a4ea5 | 1239 | bool "Enable deprecated sysfs features by default" |
7af37bec DL |
1240 | default n |
1241 | depends on SYSFS | |
1242 | depends on SYSFS_DEPRECATED | |
1243 | help | |
1244 | Enable deprecated sysfs by default. | |
1245 | ||
1246 | See the CONFIG_SYSFS_DEPRECATED option for more details about this | |
1247 | option. | |
1248 | ||
1249 | Only if you are using a new kernel on an old distribution, you might | |
1250 | need to say Y here. Even then, odds are you would not need it | |
1251 | enabled, you can always pass the boot option if absolutely necessary. | |
1252 | ||
1253 | config RELAY | |
1254 | bool "Kernel->user space relay support (formerly relayfs)" | |
1255 | help | |
1256 | This option enables support for relay interface support in | |
1257 | certain file systems (such as debugfs). | |
1258 | It is designed to provide an efficient mechanism for tools and | |
1259 | facilities to relay large amounts of data from kernel space to | |
1260 | user space. | |
1261 | ||
1262 | If unsure, say N. | |
1263 | ||
f991633d DG |
1264 | config BLK_DEV_INITRD |
1265 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | |
1266 | depends on BROKEN || !FRV | |
1267 | help | |
1268 | The initial RAM filesystem is a ramfs which is loaded by the | |
1269 | boot loader (loadlin or lilo) and that is mounted as root | |
1270 | before the normal boot procedure. It is typically used to | |
1271 | load modules needed to mount the "real" root file system, | |
1272 | etc. See <file:Documentation/initrd.txt> for details. | |
1273 | ||
1274 | If RAM disk support (BLK_DEV_RAM) is also included, this | |
1275 | also enables initial RAM disk (initrd) support and adds | |
1276 | 15 Kbytes (more on some other architectures) to the kernel size. | |
1277 | ||
1278 | If unsure say Y. | |
1279 | ||
c33df4ea JPS |
1280 | if BLK_DEV_INITRD |
1281 | ||
dbec4866 SR |
1282 | source "usr/Kconfig" |
1283 | ||
c33df4ea JPS |
1284 | endif |
1285 | ||
c45b4f1f | 1286 | config CC_OPTIMIZE_FOR_SIZE |
96fffeb4 | 1287 | bool "Optimize for size" |
c45b4f1f | 1288 | help |
31a4af7f MY |
1289 | Enabling this option will pass "-Os" instead of "-O2" to |
1290 | your compiler resulting in a smaller kernel. | |
c45b4f1f | 1291 | |
3a55fb0d | 1292 | If unsure, say N. |
c45b4f1f | 1293 | |
0847062a RD |
1294 | config SYSCTL |
1295 | bool | |
1296 | ||
b943c460 RD |
1297 | config ANON_INODES |
1298 | bool | |
1299 | ||
657a5209 MF |
1300 | config HAVE_UID16 |
1301 | bool | |
1302 | ||
1303 | config SYSCTL_EXCEPTION_TRACE | |
1304 | bool | |
1305 | help | |
1306 | Enable support for /proc/sys/debug/exception-trace. | |
1307 | ||
1308 | config SYSCTL_ARCH_UNALIGN_NO_WARN | |
1309 | bool | |
1310 | help | |
1311 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap | |
1312 | Allows arch to define/use @no_unaligned_warning to possibly warn | |
1313 | about unaligned access emulation going on under the hood. | |
1314 | ||
1315 | config SYSCTL_ARCH_UNALIGN_ALLOW | |
1316 | bool | |
1317 | help | |
1318 | Enable support for /proc/sys/kernel/unaligned-trap | |
1319 | Allows arches to define/use @unaligned_enabled to runtime toggle | |
1320 | the unaligned access emulation. | |
1321 | see arch/parisc/kernel/unaligned.c for reference | |
1322 | ||
657a5209 MF |
1323 | config HAVE_PCSPKR_PLATFORM |
1324 | bool | |
1325 | ||
f89b7755 AS |
1326 | # interpreter that classic socket filters depend on |
1327 | config BPF | |
1328 | bool | |
1329 | ||
6a108a14 DR |
1330 | menuconfig EXPERT |
1331 | bool "Configure standard kernel features (expert users)" | |
f505c553 JT |
1332 | # Unhide debug options, to make the on-by-default options visible |
1333 | select DEBUG_KERNEL | |
1da177e4 LT |
1334 | help |
1335 | This option allows certain base kernel options and settings | |
1336 | to be disabled or tweaked. This is for specialized | |
1337 | environments which can tolerate a "non-standard" kernel. | |
1338 | Only use this if you really know what you are doing. | |
1339 | ||
ae81f9e3 | 1340 | config UID16 |
6a108a14 | 1341 | bool "Enable 16-bit UID system calls" if EXPERT |
2813893f | 1342 | depends on HAVE_UID16 && MULTIUSER |
ae81f9e3 CE |
1343 | default y |
1344 | help | |
1345 | This enables the legacy 16-bit UID syscall wrappers. | |
1346 | ||
2813893f IM |
1347 | config MULTIUSER |
1348 | bool "Multiple users, groups and capabilities support" if EXPERT | |
1349 | default y | |
1350 | help | |
1351 | This option enables support for non-root users, groups and | |
1352 | capabilities. | |
1353 | ||
1354 | If you say N here, all processes will run with UID 0, GID 0, and all | |
1355 | possible capabilities. Saying N here also compiles out support for | |
1356 | system calls related to UIDs, GIDs, and capabilities, such as setuid, | |
1357 | setgid, and capset. | |
1358 | ||
1359 | If unsure, say Y here. | |
1360 | ||
f6187769 FF |
1361 | config SGETMASK_SYSCALL |
1362 | bool "sgetmask/ssetmask syscalls support" if EXPERT | |
1363 | def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH | |
1364 | ---help--- | |
1365 | sys_sgetmask and sys_ssetmask are obsolete system calls | |
1366 | no longer supported in libc but still enabled by default in some | |
1367 | architectures. | |
1368 | ||
1369 | If unsure, leave the default option here. | |
1370 | ||
6af9f7bf FF |
1371 | config SYSFS_SYSCALL |
1372 | bool "Sysfs syscall support" if EXPERT | |
1373 | default y | |
1374 | ---help--- | |
1375 | sys_sysfs is an obsolete system call no longer supported in libc. | |
1376 | Note that disabling this option is more secure but might break | |
1377 | compatibility with some systems. | |
1378 | ||
1379 | If unsure say Y here. | |
1380 | ||
b89a8171 | 1381 | config SYSCTL_SYSCALL |
6a108a14 | 1382 | bool "Sysctl syscall support" if EXPERT |
26a7034b | 1383 | depends on PROC_SYSCTL |
c736de60 | 1384 | default n |
b89a8171 | 1385 | select SYSCTL |
ae81f9e3 | 1386 | ---help--- |
13bb7e37 EB |
1387 | sys_sysctl uses binary paths that have been found challenging |
1388 | to properly maintain and use. The interface in /proc/sys | |
1389 | using paths with ascii names is now the primary path to this | |
1390 | information. | |
b89a8171 | 1391 | |
13bb7e37 EB |
1392 | Almost nothing using the binary sysctl interface so if you are |
1393 | trying to save some space it is probably safe to disable this, | |
1394 | making your kernel marginally smaller. | |
b89a8171 | 1395 | |
c736de60 | 1396 | If unsure say N here. |
ae81f9e3 | 1397 | |
1da177e4 | 1398 | config KALLSYMS |
6a108a14 | 1399 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
1da177e4 LT |
1400 | default y |
1401 | help | |
1402 | Say Y here to let the kernel print out symbolic crash information and | |
1403 | symbolic stack backtraces. This increases the size of the kernel | |
1404 | somewhat, as all symbols have to be loaded into the kernel image. | |
1405 | ||
1406 | config KALLSYMS_ALL | |
1407 | bool "Include all symbols in kallsyms" | |
1408 | depends on DEBUG_KERNEL && KALLSYMS | |
1409 | help | |
71a83ec7 AB |
1410 | Normally kallsyms only contains the symbols of functions for nicer |
1411 | OOPS messages and backtraces (i.e., symbols from the text and inittext | |
1412 | sections). This is sufficient for most cases. And only in very rare | |
1413 | cases (e.g., when a debugger is used) all symbols are required (e.g., | |
1414 | names of variables from the data sections, etc). | |
1415 | ||
1416 | This option makes sure that all symbols are loaded into the kernel | |
1417 | image (i.e., symbols from all sections) in cost of increased kernel | |
1418 | size (depending on the kernel configuration, it may be 300KiB or | |
1419 | something like this). | |
1420 | ||
1421 | Say N unless you really need all symbols. | |
d59745ce | 1422 | |
4d5d5664 AB |
1423 | config KALLSYMS_ABSOLUTE_PERCPU |
1424 | bool | |
1425 | default X86_64 && SMP | |
1426 | ||
d59745ce MM |
1427 | config PRINTK |
1428 | default y | |
6a108a14 | 1429 | bool "Enable support for printk" if EXPERT |
74876a98 | 1430 | select IRQ_WORK |
d59745ce MM |
1431 | help |
1432 | This option enables normal printk support. Removing it | |
1433 | eliminates most of the message strings from the kernel image | |
1434 | and makes the kernel more or less silent. As this makes it | |
1435 | very difficult to diagnose system problems, saying N here is | |
1436 | strongly discouraged. | |
1437 | ||
c8538a7a | 1438 | config BUG |
6a108a14 | 1439 | bool "BUG() support" if EXPERT |
c8538a7a MM |
1440 | default y |
1441 | help | |
1442 | Disabling this option eliminates support for BUG and WARN, reducing | |
1443 | the size of your kernel image and potentially quietly ignoring | |
1444 | numerous fatal conditions. You should only consider disabling this | |
1445 | option for embedded systems with no facilities for reporting errors. | |
1446 | Just say Y. | |
1447 | ||
708e9a79 | 1448 | config ELF_CORE |
046d662f | 1449 | depends on COREDUMP |
708e9a79 | 1450 | default y |
6a108a14 | 1451 | bool "Enable ELF core dumps" if EXPERT |
708e9a79 MM |
1452 | help |
1453 | Enable support for generating core dumps. Disabling saves about 4k. | |
1454 | ||
8761f1ab | 1455 | |
e5e1d3cb | 1456 | config PCSPKR_PLATFORM |
6a108a14 | 1457 | bool "Enable PC-Speaker support" if EXPERT |
8761f1ab | 1458 | depends on HAVE_PCSPKR_PLATFORM |
15f304b6 | 1459 | select I8253_LOCK |
e5e1d3cb SS |
1460 | default y |
1461 | help | |
1462 | This option allows to disable the internal PC-Speaker | |
1463 | support, saving some memory. | |
1464 | ||
1da177e4 LT |
1465 | config BASE_FULL |
1466 | default y | |
6a108a14 | 1467 | bool "Enable full-sized data structures for core" if EXPERT |
1da177e4 LT |
1468 | help |
1469 | Disabling this option reduces the size of miscellaneous core | |
1470 | kernel data structures. This saves memory on small machines, | |
1471 | but may reduce performance. | |
1472 | ||
1473 | config FUTEX | |
6a108a14 | 1474 | bool "Enable futex support" if EXPERT |
1da177e4 | 1475 | default y |
23f78d4a | 1476 | select RT_MUTEXES |
1da177e4 LT |
1477 | help |
1478 | Disabling this option will cause the kernel to be built without | |
1479 | support for "fast userspace mutexes". The resulting kernel may not | |
1480 | run glibc-based applications correctly. | |
1481 | ||
03b8c7b6 HC |
1482 | config HAVE_FUTEX_CMPXCHG |
1483 | bool | |
62b4d204 | 1484 | depends on FUTEX |
03b8c7b6 HC |
1485 | help |
1486 | Architectures should select this if futex_atomic_cmpxchg_inatomic() | |
1487 | is implemented and always working. This removes a couple of runtime | |
1488 | checks. | |
1489 | ||
1da177e4 | 1490 | config EPOLL |
6a108a14 | 1491 | bool "Enable eventpoll support" if EXPERT |
1da177e4 | 1492 | default y |
448e3cee | 1493 | select ANON_INODES |
1da177e4 LT |
1494 | help |
1495 | Disabling this option will cause the kernel to be built without | |
1496 | support for epoll family of system calls. | |
1497 | ||
fba2afaa | 1498 | config SIGNALFD |
6a108a14 | 1499 | bool "Enable signalfd() system call" if EXPERT |
448e3cee | 1500 | select ANON_INODES |
fba2afaa DL |
1501 | default y |
1502 | help | |
1503 | Enable the signalfd() system call that allows to receive signals | |
1504 | on a file descriptor. | |
1505 | ||
1506 | If unsure, say Y. | |
1507 | ||
b215e283 | 1508 | config TIMERFD |
6a108a14 | 1509 | bool "Enable timerfd() system call" if EXPERT |
448e3cee | 1510 | select ANON_INODES |
b215e283 DL |
1511 | default y |
1512 | help | |
1513 | Enable the timerfd() system call that allows to receive timer | |
1514 | events on a file descriptor. | |
1515 | ||
1516 | If unsure, say Y. | |
1517 | ||
e1ad7468 | 1518 | config EVENTFD |
6a108a14 | 1519 | bool "Enable eventfd() system call" if EXPERT |
448e3cee | 1520 | select ANON_INODES |
e1ad7468 DL |
1521 | default y |
1522 | help | |
1523 | Enable the eventfd() system call that allows to receive both | |
1524 | kernel notification (ie. KAIO) or userspace notifications. | |
1525 | ||
1526 | If unsure, say Y. | |
1527 | ||
f89b7755 AS |
1528 | # syscall, maps, verifier |
1529 | config BPF_SYSCALL | |
e1abf2cc | 1530 | bool "Enable bpf() system call" |
f89b7755 AS |
1531 | select ANON_INODES |
1532 | select BPF | |
1533 | default n | |
1534 | help | |
1535 | Enable the bpf() system call that allows to manipulate eBPF | |
1536 | programs and maps via file descriptors. | |
1537 | ||
1da177e4 | 1538 | config SHMEM |
6a108a14 | 1539 | bool "Use full shmem filesystem" if EXPERT |
1da177e4 LT |
1540 | default y |
1541 | depends on MMU | |
1542 | help | |
1543 | The shmem is an internal filesystem used to manage shared memory. | |
1544 | It is backed by swap and manages resource limits. It is also exported | |
1545 | to userspace as tmpfs if TMPFS is enabled. Disabling this | |
1546 | option replaces shmem and tmpfs with the much simpler ramfs code, | |
1547 | which may be appropriate on small systems without swap. | |
1548 | ||
ebf3f09c | 1549 | config AIO |
6a108a14 | 1550 | bool "Enable AIO support" if EXPERT |
ebf3f09c TP |
1551 | default y |
1552 | help | |
1553 | This option enables POSIX asynchronous I/O which may by used | |
657a5209 MF |
1554 | by some high performance threaded applications. Disabling |
1555 | this option saves about 7k. | |
1556 | ||
d3ac21ca JT |
1557 | config ADVISE_SYSCALLS |
1558 | bool "Enable madvise/fadvise syscalls" if EXPERT | |
1559 | default y | |
1560 | help | |
1561 | This option enables the madvise and fadvise syscalls, used by | |
1562 | applications to advise the kernel about their future memory or file | |
1563 | usage, improving performance. If building an embedded system where no | |
1564 | applications use these syscalls, you can disable this option to save | |
1565 | space. | |
1566 | ||
a14c151e AA |
1567 | config USERFAULTFD |
1568 | bool "Enable userfaultfd() system call" | |
1569 | select ANON_INODES | |
a14c151e AA |
1570 | depends on MMU |
1571 | help | |
1572 | Enable the userfaultfd() system call that allows to intercept and | |
1573 | handle page faults in userland. | |
1574 | ||
657a5209 MF |
1575 | config PCI_QUIRKS |
1576 | default y | |
1577 | bool "Enable PCI quirk workarounds" if EXPERT | |
1578 | depends on PCI | |
1579 | help | |
1580 | This enables workarounds for various PCI chipset | |
1581 | bugs/quirks. Disable this only if your target machine is | |
1582 | unaffected by PCI quirks. | |
ebf3f09c | 1583 | |
5b25b13a MD |
1584 | config MEMBARRIER |
1585 | bool "Enable membarrier() system call" if EXPERT | |
1586 | default y | |
1587 | help | |
1588 | Enable the membarrier() system call that allows issuing memory | |
1589 | barriers across all running threads, which can be used to distribute | |
1590 | the cost of user-space memory barriers asymmetrically by transforming | |
1591 | pairs of memory barriers into pairs consisting of membarrier() and a | |
1592 | compiler barrier. | |
1593 | ||
1594 | If unsure, say Y. | |
1595 | ||
6befe5f6 RD |
1596 | config EMBEDDED |
1597 | bool "Embedded system" | |
5d2acfc7 | 1598 | option allnoconfig_y |
6befe5f6 RD |
1599 | select EXPERT |
1600 | help | |
1601 | This option should be enabled if compiling the kernel for | |
1602 | an embedded system so certain expert options are available | |
1603 | for configuration. | |
1604 | ||
cdd6c482 | 1605 | config HAVE_PERF_EVENTS |
0793a61d | 1606 | bool |
018df72d MF |
1607 | help |
1608 | See tools/perf/design.txt for details. | |
0793a61d | 1609 | |
906010b2 PZ |
1610 | config PERF_USE_VMALLOC |
1611 | bool | |
1612 | help | |
1613 | See tools/perf/design.txt for details | |
1614 | ||
57c0c15b | 1615 | menu "Kernel Performance Events And Counters" |
0793a61d | 1616 | |
cdd6c482 | 1617 | config PERF_EVENTS |
57c0c15b | 1618 | bool "Kernel performance events and counters" |
392d65a9 | 1619 | default y if PROFILING |
cdd6c482 | 1620 | depends on HAVE_PERF_EVENTS |
4c59e467 | 1621 | select ANON_INODES |
e360adbe | 1622 | select IRQ_WORK |
83fe27ea | 1623 | select SRCU |
0793a61d | 1624 | help |
57c0c15b IM |
1625 | Enable kernel support for various performance events provided |
1626 | by software and hardware. | |
0793a61d | 1627 | |
dd77038d | 1628 | Software events are supported either built-in or via the |
57c0c15b | 1629 | use of generic tracepoints. |
0793a61d | 1630 | |
57c0c15b IM |
1631 | Most modern CPUs support performance events via performance |
1632 | counter registers. These registers count the number of certain | |
0793a61d TG |
1633 | types of hw events: such as instructions executed, cachemisses |
1634 | suffered, or branches mis-predicted - without slowing down the | |
1635 | kernel or applications. These registers can also trigger interrupts | |
1636 | when a threshold number of events have passed - and can thus be | |
1637 | used to profile the code that runs on that CPU. | |
1638 | ||
57c0c15b | 1639 | The Linux Performance Event subsystem provides an abstraction of |
dd77038d | 1640 | these software and hardware event capabilities, available via a |
57c0c15b | 1641 | system call and used by the "perf" utility in tools/perf/. It |
0793a61d TG |
1642 | provides per task and per CPU counters, and it provides event |
1643 | capabilities on top of those. | |
1644 | ||
1645 | Say Y if unsure. | |
1646 | ||
906010b2 PZ |
1647 | config DEBUG_PERF_USE_VMALLOC |
1648 | default n | |
1649 | bool "Debug: use vmalloc to back perf mmap() buffers" | |
cb307113 | 1650 | depends on PERF_EVENTS && DEBUG_KERNEL && !PPC |
906010b2 PZ |
1651 | select PERF_USE_VMALLOC |
1652 | help | |
1653 | Use vmalloc memory to back perf mmap() buffers. | |
1654 | ||
1655 | Mostly useful for debugging the vmalloc code on platforms | |
1656 | that don't require it. | |
1657 | ||
1658 | Say N if unsure. | |
1659 | ||
0793a61d TG |
1660 | endmenu |
1661 | ||
f8891e5e CL |
1662 | config VM_EVENT_COUNTERS |
1663 | default y | |
6a108a14 | 1664 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
f8891e5e | 1665 | help |
2aea4fb6 PJ |
1666 | VM event counters are needed for event counts to be shown. |
1667 | This option allows the disabling of the VM event counters | |
6a108a14 | 1668 | on EXPERT systems. /proc/vmstat will only show page counts |
2aea4fb6 | 1669 | if VM event counters are disabled. |
f8891e5e | 1670 | |
41ecc55b CL |
1671 | config SLUB_DEBUG |
1672 | default y | |
6a108a14 | 1673 | bool "Enable SLUB debugging support" if EXPERT |
f6acb635 | 1674 | depends on SLUB && SYSFS |
41ecc55b CL |
1675 | help |
1676 | SLUB has extensive debug support features. Disabling these can | |
1677 | result in significant savings in code size. This also disables | |
1678 | SLUB sysfs support. /sys/slab will not exist and there will be | |
1679 | no support for cache validation etc. | |
1680 | ||
b943c460 RD |
1681 | config COMPAT_BRK |
1682 | bool "Disable heap randomization" | |
1683 | default y | |
1684 | help | |
1685 | Randomizing heap placement makes heap exploits harder, but it | |
1686 | also breaks ancient binaries (including anything libc5 based). | |
1687 | This option changes the bootup default to heap randomization | |
692105b8 | 1688 | disabled, and can be overridden at runtime by setting |
b943c460 RD |
1689 | /proc/sys/kernel/randomize_va_space to 2. |
1690 | ||
1691 | On non-ancient distros (post-2000 ones) N is usually a safe choice. | |
1692 | ||
81819f0f CL |
1693 | choice |
1694 | prompt "Choose SLAB allocator" | |
a0acd820 | 1695 | default SLUB |
81819f0f CL |
1696 | help |
1697 | This option allows to select a slab allocator. | |
1698 | ||
1699 | config SLAB | |
1700 | bool "SLAB" | |
1701 | help | |
1702 | The regular slab allocator that is established and known to work | |
34013886 | 1703 | well in all environments. It organizes cache hot objects in |
02f56210 | 1704 | per cpu and per node queues. |
81819f0f CL |
1705 | |
1706 | config SLUB | |
81819f0f CL |
1707 | bool "SLUB (Unqueued Allocator)" |
1708 | help | |
1709 | SLUB is a slab allocator that minimizes cache line usage | |
1710 | instead of managing queues of cached objects (SLAB approach). | |
1711 | Per cpu caching is realized using slabs of objects instead | |
1712 | of queues of objects. SLUB can use memory efficiently | |
02f56210 SA |
1713 | and has enhanced diagnostics. SLUB is the default choice for |
1714 | a slab allocator. | |
81819f0f CL |
1715 | |
1716 | config SLOB | |
6a108a14 | 1717 | depends on EXPERT |
81819f0f CL |
1718 | bool "SLOB (Simple Allocator)" |
1719 | help | |
37291458 MM |
1720 | SLOB replaces the stock allocator with a drastically simpler |
1721 | allocator. SLOB is generally more space efficient but | |
1722 | does not perform as well on large systems. | |
81819f0f CL |
1723 | |
1724 | endchoice | |
1725 | ||
345c905d JK |
1726 | config SLUB_CPU_PARTIAL |
1727 | default y | |
b39ffbf8 | 1728 | depends on SLUB && SMP |
345c905d JK |
1729 | bool "SLUB per cpu partial cache" |
1730 | help | |
1731 | Per cpu partial caches accellerate objects allocation and freeing | |
1732 | that is local to a processor at the price of more indeterminism | |
1733 | in the latency of the free. On overflow these caches will be cleared | |
1734 | which requires the taking of locks that may cause latency spikes. | |
1735 | Typically one would choose no for a realtime system. | |
1736 | ||
ea637639 JZ |
1737 | config MMAP_ALLOW_UNINITIALIZED |
1738 | bool "Allow mmapped anonymous memory to be uninitialized" | |
6a108a14 | 1739 | depends on EXPERT && !MMU |
ea637639 JZ |
1740 | default n |
1741 | help | |
1742 | Normally, and according to the Linux spec, anonymous memory obtained | |
1743 | from mmap() has it's contents cleared before it is passed to | |
1744 | userspace. Enabling this config option allows you to request that | |
1745 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus | |
1746 | providing a huge performance boost. If this option is not enabled, | |
1747 | then the flag will be ignored. | |
1748 | ||
1749 | This is taken advantage of by uClibc's malloc(), and also by | |
1750 | ELF-FDPIC binfmt's brk and stack allocator. | |
1751 | ||
1752 | Because of the obvious security issues, this option should only be | |
1753 | enabled on embedded devices where you control what is run in | |
1754 | userspace. Since that isn't generally a problem on no-MMU systems, | |
1755 | it is normally safe to say Y here. | |
1756 | ||
1757 | See Documentation/nommu-mmap.txt for more information. | |
1758 | ||
091f6e26 DH |
1759 | config SYSTEM_DATA_VERIFICATION |
1760 | def_bool n | |
1761 | select SYSTEM_TRUSTED_KEYRING | |
1762 | select KEYS | |
1763 | select CRYPTO | |
1764 | select ASYMMETRIC_KEY_TYPE | |
1765 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE | |
1766 | select PUBLIC_KEY_ALGO_RSA | |
1767 | select ASN1 | |
1768 | select OID_REGISTRY | |
1769 | select X509_CERTIFICATE_PARSER | |
1770 | select PKCS7_MESSAGE_PARSER | |
82c04ff8 | 1771 | help |
091f6e26 DH |
1772 | Provide PKCS#7 message verification using the contents of the system |
1773 | trusted keyring to provide public keys. This then can be used for | |
1774 | module verification, kexec image verification and firmware blob | |
1775 | verification. | |
82c04ff8 | 1776 | |
125e5645 | 1777 | config PROFILING |
b309a294 | 1778 | bool "Profiling support" |
125e5645 MD |
1779 | help |
1780 | Say Y here to enable the extended profiling support mechanisms used | |
1781 | by profilers such as OProfile. | |
1782 | ||
5f87f112 IM |
1783 | # |
1784 | # Place an empty function call at each tracepoint site. Can be | |
1785 | # dynamically changed for a probe function. | |
1786 | # | |
97e1c18e | 1787 | config TRACEPOINTS |
5f87f112 | 1788 | bool |
97e1c18e | 1789 | |
fb32e03f MD |
1790 | source "arch/Kconfig" |
1791 | ||
1da177e4 LT |
1792 | endmenu # General setup |
1793 | ||
ee7e5516 DES |
1794 | config HAVE_GENERIC_DMA_COHERENT |
1795 | bool | |
1796 | default n | |
1797 | ||
158a9624 LT |
1798 | config SLABINFO |
1799 | bool | |
1800 | depends on PROC_FS | |
0f389ec6 | 1801 | depends on SLAB || SLUB_DEBUG |
158a9624 LT |
1802 | default y |
1803 | ||
ae81f9e3 | 1804 | config RT_MUTEXES |
6341e62b | 1805 | bool |
ae81f9e3 | 1806 | |
1da177e4 LT |
1807 | config BASE_SMALL |
1808 | int | |
1809 | default 0 if BASE_FULL | |
1810 | default 1 if !BASE_FULL | |
1811 | ||
66da5733 | 1812 | menuconfig MODULES |
1da177e4 | 1813 | bool "Enable loadable module support" |
11097a03 | 1814 | option modules |
1da177e4 LT |
1815 | help |
1816 | Kernel modules are small pieces of compiled code which can | |
1817 | be inserted in the running kernel, rather than being | |
1818 | permanently built into the kernel. You use the "modprobe" | |
1819 | tool to add (and sometimes remove) them. If you say Y here, | |
1820 | many parts of the kernel can be built as modules (by | |
1821 | answering M instead of Y where indicated): this is most | |
1822 | useful for infrequently used options which are not required | |
1823 | for booting. For more information, see the man pages for | |
1824 | modprobe, lsmod, modinfo, insmod and rmmod. | |
1825 | ||
1826 | If you say Y here, you will need to run "make | |
1827 | modules_install" to put the modules under /lib/modules/ | |
1828 | where modprobe can find them (you may need to be root to do | |
1829 | this). | |
1830 | ||
1831 | If unsure, say Y. | |
1832 | ||
0b0de144 RD |
1833 | if MODULES |
1834 | ||
826e4506 LT |
1835 | config MODULE_FORCE_LOAD |
1836 | bool "Forced module loading" | |
826e4506 LT |
1837 | default n |
1838 | help | |
91e37a79 RR |
1839 | Allow loading of modules without version information (ie. modprobe |
1840 | --force). Forced module loading sets the 'F' (forced) taint flag and | |
1841 | is usually a really bad idea. | |
826e4506 | 1842 | |
1da177e4 LT |
1843 | config MODULE_UNLOAD |
1844 | bool "Module unloading" | |
1da177e4 LT |
1845 | help |
1846 | Without this option you will not be able to unload any | |
1847 | modules (note that some modules may not be unloadable | |
f7f5b675 DV |
1848 | anyway), which makes your kernel smaller, faster |
1849 | and simpler. If unsure, say Y. | |
1da177e4 LT |
1850 | |
1851 | config MODULE_FORCE_UNLOAD | |
1852 | bool "Forced module unloading" | |
19c92399 | 1853 | depends on MODULE_UNLOAD |
1da177e4 LT |
1854 | help |
1855 | This option allows you to force a module to unload, even if the | |
1856 | kernel believes it is unsafe: the kernel will remove the module | |
1857 | without waiting for anyone to stop using it (using the -f option to | |
1858 | rmmod). This is mainly for kernel developers and desperate users. | |
1859 | If unsure, say N. | |
1860 | ||
1da177e4 | 1861 | config MODVERSIONS |
0d541643 | 1862 | bool "Module versioning support" |
1da177e4 LT |
1863 | help |
1864 | Usually, you have to use modules compiled with your kernel. | |
1865 | Saying Y here makes it sometimes possible to use modules | |
1866 | compiled for different kernels, by adding enough information | |
1867 | to the modules to (hopefully) spot any changes which would | |
1868 | make them incompatible with the kernel you are running. If | |
1869 | unsure, say N. | |
1870 | ||
1871 | config MODULE_SRCVERSION_ALL | |
1872 | bool "Source checksum for all modules" | |
1da177e4 LT |
1873 | help |
1874 | Modules which contain a MODULE_VERSION get an extra "srcversion" | |
1875 | field inserted into their modinfo section, which contains a | |
1876 | sum of the source files which made it. This helps maintainers | |
1877 | see exactly which source was used to build a module (since | |
1878 | others sometimes change the module source without updating | |
1879 | the version). With this option, such a "srcversion" field | |
1880 | will be created for all modules. If unsure, say N. | |
1881 | ||
106a4ee2 RR |
1882 | config MODULE_SIG |
1883 | bool "Module signature verification" | |
1884 | depends on MODULES | |
091f6e26 | 1885 | select SYSTEM_DATA_VERIFICATION |
106a4ee2 RR |
1886 | help |
1887 | Check modules for valid signatures upon load: the signature | |
1888 | is simply appended to the module. For more information see | |
1889 | Documentation/module-signing.txt. | |
1890 | ||
228c37ff DH |
1891 | Note that this option adds the OpenSSL development packages as a |
1892 | kernel build dependency so that the signing tool can use its crypto | |
1893 | library. | |
1894 | ||
ea0b6dcf DH |
1895 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
1896 | module DOES NOT get stripped after being signed. This includes the | |
1897 | debuginfo strip done by some packagers (such as rpmbuild) and | |
1898 | inclusion into an initramfs that wants the module size reduced. | |
1899 | ||
106a4ee2 RR |
1900 | config MODULE_SIG_FORCE |
1901 | bool "Require modules to be validly signed" | |
1902 | depends on MODULE_SIG | |
1903 | help | |
1904 | Reject unsigned modules or signed modules for which we don't have a | |
1905 | key. Without this, such modules will simply taint the kernel. | |
ea0b6dcf | 1906 | |
d9d8d7ed MM |
1907 | config MODULE_SIG_ALL |
1908 | bool "Automatically sign all modules" | |
1909 | default y | |
1910 | depends on MODULE_SIG | |
1911 | help | |
1912 | Sign all modules during make modules_install. Without this option, | |
1913 | modules must be signed manually, using the scripts/sign-file tool. | |
1914 | ||
1915 | comment "Do not forget to sign required modules with scripts/sign-file" | |
1916 | depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL | |
1917 | ||
ea0b6dcf DH |
1918 | choice |
1919 | prompt "Which hash algorithm should modules be signed with?" | |
1920 | depends on MODULE_SIG | |
1921 | help | |
1922 | This determines which sort of hashing algorithm will be used during | |
1923 | signature generation. This algorithm _must_ be built into the kernel | |
1924 | directly so that signature verification can take place. It is not | |
1925 | possible to load a signed module containing the algorithm to check | |
1926 | the signature on that module. | |
1927 | ||
1928 | config MODULE_SIG_SHA1 | |
1929 | bool "Sign modules with SHA-1" | |
1930 | select CRYPTO_SHA1 | |
1931 | ||
1932 | config MODULE_SIG_SHA224 | |
1933 | bool "Sign modules with SHA-224" | |
1934 | select CRYPTO_SHA256 | |
1935 | ||
1936 | config MODULE_SIG_SHA256 | |
1937 | bool "Sign modules with SHA-256" | |
1938 | select CRYPTO_SHA256 | |
1939 | ||
1940 | config MODULE_SIG_SHA384 | |
1941 | bool "Sign modules with SHA-384" | |
1942 | select CRYPTO_SHA512 | |
1943 | ||
1944 | config MODULE_SIG_SHA512 | |
1945 | bool "Sign modules with SHA-512" | |
1946 | select CRYPTO_SHA512 | |
1947 | ||
1948 | endchoice | |
1949 | ||
22753674 MM |
1950 | config MODULE_SIG_HASH |
1951 | string | |
1952 | depends on MODULE_SIG | |
1953 | default "sha1" if MODULE_SIG_SHA1 | |
1954 | default "sha224" if MODULE_SIG_SHA224 | |
1955 | default "sha256" if MODULE_SIG_SHA256 | |
1956 | default "sha384" if MODULE_SIG_SHA384 | |
1957 | default "sha512" if MODULE_SIG_SHA512 | |
1958 | ||
beb50df3 BJ |
1959 | config MODULE_COMPRESS |
1960 | bool "Compress modules on installation" | |
1961 | depends on MODULES | |
1962 | help | |
beb50df3 | 1963 | |
b6c09b51 RR |
1964 | Compresses kernel modules when 'make modules_install' is run; gzip or |
1965 | xz depending on "Compression algorithm" below. | |
beb50df3 | 1966 | |
b6c09b51 | 1967 | module-init-tools MAY support gzip, and kmod MAY support gzip and xz. |
beb50df3 | 1968 | |
b6c09b51 RR |
1969 | Out-of-tree kernel modules installed using Kbuild will also be |
1970 | compressed upon installation. | |
beb50df3 | 1971 | |
b6c09b51 RR |
1972 | Note: for modules inside an initrd or initramfs, it's more efficient |
1973 | to compress the whole initrd or initramfs instead. | |
beb50df3 | 1974 | |
b6c09b51 RR |
1975 | Note: This is fully compatible with signed modules. |
1976 | ||
1977 | If in doubt, say N. | |
beb50df3 BJ |
1978 | |
1979 | choice | |
1980 | prompt "Compression algorithm" | |
1981 | depends on MODULE_COMPRESS | |
1982 | default MODULE_COMPRESS_GZIP | |
1983 | help | |
1984 | This determines which sort of compression will be used during | |
1985 | 'make modules_install'. | |
1986 | ||
1987 | GZIP (default) and XZ are supported. | |
1988 | ||
1989 | config MODULE_COMPRESS_GZIP | |
1990 | bool "GZIP" | |
1991 | ||
1992 | config MODULE_COMPRESS_XZ | |
1993 | bool "XZ" | |
1994 | ||
1995 | endchoice | |
1996 | ||
0b0de144 RD |
1997 | endif # MODULES |
1998 | ||
6c9692e2 PZ |
1999 | config MODULES_TREE_LOOKUP |
2000 | def_bool y | |
2001 | depends on PERF_EVENTS || TRACING | |
2002 | ||
98a79d6a RR |
2003 | config INIT_ALL_POSSIBLE |
2004 | bool | |
2005 | help | |
5f054e31 RR |
2006 | Back when each arch used to define their own cpu_online_mask and |
2007 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask | |
98a79d6a RR |
2008 | with all 1s, and others with all 0s. When they were centralised, |
2009 | it was better to provide this option than to break all the archs | |
692105b8 | 2010 | and have several arch maintainers pursuing me down dark alleys. |
98a79d6a | 2011 | |
3a65dfe8 | 2012 | source "block/Kconfig" |
e98c3202 AK |
2013 | |
2014 | config PREEMPT_NOTIFIERS | |
2015 | bool | |
e260be67 | 2016 | |
16295bec SK |
2017 | config PADATA |
2018 | depends on SMP | |
2019 | bool | |
2020 | ||
754b7b63 AK |
2021 | # Can be selected by architectures with broken toolchains |
2022 | # that get confused by correct const<->read_only section | |
2023 | # mappings | |
2024 | config BROKEN_RODATA | |
2025 | bool | |
2026 | ||
4520c6a4 DH |
2027 | config ASN1 |
2028 | tristate | |
2029 | help | |
2030 | Build a simple ASN.1 grammar compiler that produces a bytecode output | |
2031 | that can be interpreted by the ASN.1 stream decoder and used to | |
2032 | inform it as to what tags are to be expected in a stream and what | |
2033 | functions to call on what tags. | |
2034 | ||
6beb0009 | 2035 | source "kernel/Kconfig.locks" |