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 | ||
1da177e4 LT |
56 | config LOCALVERSION |
57 | string "Local version - append to kernel release" | |
58 | help | |
59 | Append an extra string to the end of your kernel version. | |
60 | This will show up when you type uname, for example. | |
61 | The string you set here will be appended after the contents of | |
62 | any files with a filename matching localversion* in your | |
63 | object and source tree, in that order. Your total string can | |
64 | be a maximum of 64 characters. | |
65 | ||
aaebf433 RA |
66 | config LOCALVERSION_AUTO |
67 | bool "Automatically append version information to the version string" | |
68 | default y | |
69 | help | |
70 | This will try to automatically determine if the current tree is a | |
6e5a5420 RD |
71 | release tree by looking for git tags that belong to the current |
72 | top of tree revision. | |
aaebf433 RA |
73 | |
74 | A string of the format -gxxxxxxxx will be added to the localversion | |
6e5a5420 | 75 | if a git-based tree is found. The string generated by this will be |
aaebf433 | 76 | appended after any matching localversion* files, and after the value |
6e5a5420 | 77 | set in CONFIG_LOCALVERSION. |
aaebf433 | 78 | |
6e5a5420 RD |
79 | (The actual string used here is the first eight characters produced |
80 | by running the command: | |
81 | ||
82 | $ git rev-parse --verify HEAD | |
83 | ||
84 | which is done within the script "scripts/setlocalversion".) | |
aaebf433 | 85 | |
2e9f3bdd PA |
86 | config HAVE_KERNEL_GZIP |
87 | bool | |
88 | ||
89 | config HAVE_KERNEL_BZIP2 | |
90 | bool | |
91 | ||
92 | config HAVE_KERNEL_LZMA | |
93 | bool | |
94 | ||
3ebe1243 LC |
95 | config HAVE_KERNEL_XZ |
96 | bool | |
97 | ||
7dd65feb AT |
98 | config HAVE_KERNEL_LZO |
99 | bool | |
100 | ||
30d65dbf | 101 | choice |
2e9f3bdd PA |
102 | prompt "Kernel compression mode" |
103 | default KERNEL_GZIP | |
3ebe1243 | 104 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO |
2e9f3bdd | 105 | help |
30d65dbf AK |
106 | The linux kernel is a kind of self-extracting executable. |
107 | Several compression algorithms are available, which differ | |
108 | in efficiency, compression and decompression speed. | |
109 | Compression speed is only relevant when building a kernel. | |
110 | Decompression speed is relevant at each boot. | |
111 | ||
112 | If you have any problems with bzip2 or lzma compressed | |
113 | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older | |
114 | version of this functionality (bzip2 only), for 2.4, was | |
115 | supplied by Christian Ludwig) | |
116 | ||
117 | High compression options are mostly useful for users, who | |
118 | are low on disk space (embedded systems), but for whom ram | |
119 | size matters less. | |
120 | ||
121 | If in doubt, select 'gzip' | |
122 | ||
123 | config KERNEL_GZIP | |
2e9f3bdd PA |
124 | bool "Gzip" |
125 | depends on HAVE_KERNEL_GZIP | |
126 | help | |
7dd65feb AT |
127 | The old and tried gzip compression. It provides a good balance |
128 | between compression ratio and decompression speed. | |
30d65dbf AK |
129 | |
130 | config KERNEL_BZIP2 | |
131 | bool "Bzip2" | |
2e9f3bdd | 132 | depends on HAVE_KERNEL_BZIP2 |
30d65dbf AK |
133 | help |
134 | Its compression ratio and speed is intermediate. | |
0a4dd35c | 135 | Decompression speed is slowest among the choices. The kernel |
2e9f3bdd PA |
136 | size is about 10% smaller with bzip2, in comparison to gzip. |
137 | Bzip2 uses a large amount of memory. For modern kernels you | |
138 | will need at least 8MB RAM or more for booting. | |
30d65dbf AK |
139 | |
140 | config KERNEL_LZMA | |
2e9f3bdd PA |
141 | bool "LZMA" |
142 | depends on HAVE_KERNEL_LZMA | |
143 | help | |
0a4dd35c RD |
144 | This compression algorithm's ratio is best. Decompression speed |
145 | is between gzip and bzip2. Compression is slowest. | |
146 | The kernel size is about 33% smaller with LZMA in comparison to gzip. | |
30d65dbf | 147 | |
3ebe1243 LC |
148 | config KERNEL_XZ |
149 | bool "XZ" | |
150 | depends on HAVE_KERNEL_XZ | |
151 | help | |
152 | XZ uses the LZMA2 algorithm and instruction set specific | |
153 | BCJ filters which can improve compression ratio of executable | |
154 | code. The size of the kernel is about 30% smaller with XZ in | |
155 | comparison to gzip. On architectures for which there is a BCJ | |
156 | filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ | |
157 | will create a few percent smaller kernel than plain LZMA. | |
158 | ||
159 | The speed is about the same as with LZMA: The decompression | |
160 | speed of XZ is better than that of bzip2 but worse than gzip | |
161 | and LZO. Compression is slow. | |
162 | ||
7dd65feb AT |
163 | config KERNEL_LZO |
164 | bool "LZO" | |
165 | depends on HAVE_KERNEL_LZO | |
166 | help | |
0a4dd35c | 167 | Its compression ratio is the poorest among the choices. The kernel |
681b3049 | 168 | size is about 10% bigger than gzip; however its speed |
7dd65feb AT |
169 | (both compression and decompression) is the fastest. |
170 | ||
30d65dbf AK |
171 | endchoice |
172 | ||
bd5dc17b JT |
173 | config DEFAULT_HOSTNAME |
174 | string "Default hostname" | |
175 | default "(none)" | |
176 | help | |
177 | This option determines the default system hostname before userspace | |
178 | calls sethostname(2). The kernel traditionally uses "(none)" here, | |
179 | but you may wish to use a different default here to make a minimal | |
180 | system more usable with less configuration. | |
181 | ||
1da177e4 LT |
182 | config SWAP |
183 | bool "Support for paging of anonymous memory (swap)" | |
9361401e | 184 | depends on MMU && BLOCK |
1da177e4 LT |
185 | default y |
186 | help | |
187 | This option allows you to choose whether you want to have support | |
92c3504e | 188 | for so called swap devices or swap files in your kernel that are |
1da177e4 LT |
189 | used to provide more virtual memory than the actual RAM present |
190 | in your computer. If unsure say Y. | |
191 | ||
192 | config SYSVIPC | |
193 | bool "System V IPC" | |
1da177e4 LT |
194 | ---help--- |
195 | Inter Process Communication is a suite of library functions and | |
196 | system calls which let processes (running programs) synchronize and | |
197 | exchange information. It is generally considered to be a good thing, | |
198 | and some programs won't run unless you say Y here. In particular, if | |
199 | you want to run the DOS emulator dosemu under Linux (read the | |
200 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), | |
201 | you'll need to say Y here. | |
202 | ||
203 | You can find documentation about IPC with "info ipc" and also in | |
204 | section 6.4 of the Linux Programmer's Guide, available from | |
205 | <http://www.tldp.org/guides.html>. | |
206 | ||
a5494dcd EB |
207 | config SYSVIPC_SYSCTL |
208 | bool | |
209 | depends on SYSVIPC | |
210 | depends on SYSCTL | |
211 | default y | |
212 | ||
1da177e4 LT |
213 | config POSIX_MQUEUE |
214 | bool "POSIX Message Queues" | |
19c92399 | 215 | depends on NET |
1da177e4 LT |
216 | ---help--- |
217 | POSIX variant of message queues is a part of IPC. In POSIX message | |
218 | queues every message has a priority which decides about succession | |
219 | of receiving it by a process. If you want to compile and run | |
220 | programs written e.g. for Solaris with use of its POSIX message | |
b0e37650 | 221 | queues (functions mq_*) say Y here. |
1da177e4 LT |
222 | |
223 | POSIX message queues are visible as a filesystem called 'mqueue' | |
224 | and can be mounted somewhere if you want to do filesystem | |
225 | operations on message queues. | |
226 | ||
227 | If unsure, say Y. | |
228 | ||
bdc8e5f8 SH |
229 | config POSIX_MQUEUE_SYSCTL |
230 | bool | |
231 | depends on POSIX_MQUEUE | |
232 | depends on SYSCTL | |
233 | default y | |
234 | ||
391dc69c FW |
235 | config FHANDLE |
236 | bool "open by fhandle syscalls" | |
237 | select EXPORTFS | |
238 | help | |
239 | If you say Y here, a user level program will be able to map | |
240 | file names to handle and then later use the handle for | |
241 | different file system operations. This is useful in implementing | |
242 | userspace file servers, which now track files using handles instead | |
243 | of names. The handle would remain the same even if file names | |
244 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) | |
245 | syscalls. | |
246 | ||
247 | config AUDIT | |
248 | bool "Auditing support" | |
249 | depends on NET | |
250 | help | |
251 | Enable auditing infrastructure that can be used with another | |
252 | kernel subsystem, such as SELinux (which requires this for | |
253 | logging of avc messages output). Does not do system-call | |
254 | auditing without CONFIG_AUDITSYSCALL. | |
255 | ||
256 | config AUDITSYSCALL | |
257 | bool "Enable system-call auditing support" | |
258 | depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) | |
259 | default y if SECURITY_SELINUX | |
260 | help | |
261 | Enable low-overhead system-call auditing infrastructure that | |
262 | can be used independently or with another kernel subsystem, | |
263 | such as SELinux. | |
264 | ||
265 | config AUDIT_WATCH | |
266 | def_bool y | |
267 | depends on AUDITSYSCALL | |
268 | select FSNOTIFY | |
269 | ||
270 | config AUDIT_TREE | |
271 | def_bool y | |
272 | depends on AUDITSYSCALL | |
273 | select FSNOTIFY | |
274 | ||
275 | config AUDIT_LOGINUID_IMMUTABLE | |
276 | bool "Make audit loginuid immutable" | |
277 | depends on AUDIT | |
278 | help | |
279 | The config option toggles if a task setting its loginuid requires | |
280 | CAP_SYS_AUDITCONTROL or if that task should require no special permissions | |
281 | but should instead only allow setting its loginuid if it was never | |
282 | previously set. On systems which use systemd or a similar central | |
283 | process to restart login services this should be set to true. On older | |
284 | systems in which an admin would typically have to directly stop and | |
285 | start processes this should be set to false. Setting this to true allows | |
286 | one to drop potentially dangerous capabilites from the login tasks, | |
287 | but may not be backwards compatible with older init systems. | |
288 | ||
289 | source "kernel/irq/Kconfig" | |
290 | source "kernel/time/Kconfig" | |
291 | ||
292 | menu "CPU/Task time and stats accounting" | |
293 | ||
abf917cd FW |
294 | config VIRT_CPU_ACCOUNTING |
295 | bool | |
296 | ||
fdf9c356 FW |
297 | choice |
298 | prompt "Cputime accounting" | |
299 | default TICK_CPU_ACCOUNTING if !PPC64 | |
02fc8d37 | 300 | default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
fdf9c356 FW |
301 | |
302 | # Kind of a stub config for the pure tick based cputime accounting | |
303 | config TICK_CPU_ACCOUNTING | |
304 | bool "Simple tick based cputime accounting" | |
c58b0df1 | 305 | depends on !S390 && !NO_HZ_FULL |
fdf9c356 FW |
306 | help |
307 | This is the basic tick based cputime accounting that maintains | |
308 | statistics about user, system and idle time spent on per jiffies | |
309 | granularity. | |
310 | ||
311 | If unsure, say Y. | |
312 | ||
abf917cd | 313 | config VIRT_CPU_ACCOUNTING_NATIVE |
b952741c | 314 | bool "Deterministic task and CPU time accounting" |
c58b0df1 | 315 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
abf917cd | 316 | select VIRT_CPU_ACCOUNTING |
b952741c FW |
317 | help |
318 | Select this option to enable more accurate task and CPU time | |
319 | accounting. This is done by reading a CPU counter on each | |
320 | kernel entry and exit and on transitions within the kernel | |
321 | between system, softirq and hardirq state, so there is a | |
322 | small performance impact. In the case of s390 or IBM POWER > 5, | |
323 | this also enables accounting of stolen time on logically-partitioned | |
324 | systems. | |
325 | ||
abf917cd FW |
326 | config VIRT_CPU_ACCOUNTING_GEN |
327 | bool "Full dynticks CPU time accounting" | |
328 | depends on HAVE_CONTEXT_TRACKING && 64BIT | |
329 | select VIRT_CPU_ACCOUNTING | |
330 | select CONTEXT_TRACKING | |
331 | help | |
332 | Select this option to enable task and CPU time accounting on full | |
333 | dynticks systems. This accounting is implemented by watching every | |
334 | kernel-user boundaries using the context tracking subsystem. | |
335 | The accounting is thus performed at the expense of some significant | |
336 | overhead. | |
337 | ||
338 | For now this is only useful if you are working on the full | |
339 | dynticks subsystem development. | |
340 | ||
341 | If unsure, say N. | |
342 | ||
fdf9c356 FW |
343 | config IRQ_TIME_ACCOUNTING |
344 | bool "Fine granularity task level IRQ time accounting" | |
c58b0df1 | 345 | depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL |
fdf9c356 FW |
346 | help |
347 | Select this option to enable fine granularity task irq time | |
348 | accounting. This is done by reading a timestamp on each | |
349 | transitions between softirq and hardirq state, so there can be a | |
350 | small performance impact. | |
351 | ||
352 | If in doubt, say N here. | |
353 | ||
354 | endchoice | |
355 | ||
1da177e4 LT |
356 | config BSD_PROCESS_ACCT |
357 | bool "BSD Process Accounting" | |
358 | help | |
359 | If you say Y here, a user level program will be able to instruct the | |
360 | kernel (via a special system call) to write process accounting | |
361 | information to a file: whenever a process exits, information about | |
362 | that process will be appended to the file by the kernel. The | |
363 | information includes things such as creation time, owning user, | |
364 | command name, memory usage, controlling terminal etc. (the complete | |
365 | list is in the struct acct in <file:include/linux/acct.h>). It is | |
366 | up to the user level program to do useful things with this | |
367 | information. This is generally a good idea, so say Y. | |
368 | ||
369 | config BSD_PROCESS_ACCT_V3 | |
370 | bool "BSD Process Accounting version 3 file format" | |
371 | depends on BSD_PROCESS_ACCT | |
372 | default n | |
373 | help | |
374 | If you say Y here, the process accounting information is written | |
375 | in a new file format that also logs the process IDs of each | |
376 | process and it's parent. Note that this file format is incompatible | |
377 | with previous v0/v1/v2 file formats, so you will need updated tools | |
378 | for processing it. A preliminary version of these tools is available | |
37a4c940 | 379 | at <http://www.gnu.org/software/acct/>. |
1da177e4 | 380 | |
c757249a | 381 | config TASKSTATS |
19c92399 | 382 | bool "Export task/process statistics through netlink" |
c757249a SN |
383 | depends on NET |
384 | default n | |
385 | help | |
386 | Export selected statistics for tasks/processes through the | |
387 | generic netlink interface. Unlike BSD process accounting, the | |
388 | statistics are available during the lifetime of tasks/processes as | |
389 | responses to commands. Like BSD accounting, they are sent to user | |
390 | space on task exit. | |
391 | ||
392 | Say N if unsure. | |
393 | ||
ca74e92b | 394 | config TASK_DELAY_ACCT |
19c92399 | 395 | bool "Enable per-task delay accounting" |
6f44993f | 396 | depends on TASKSTATS |
ca74e92b SN |
397 | help |
398 | Collect information on time spent by a task waiting for system | |
399 | resources like cpu, synchronous block I/O completion and swapping | |
400 | in pages. Such statistics can help in setting a task's priorities | |
401 | relative to other tasks for cpu, io, rss limits etc. | |
402 | ||
403 | Say N if unsure. | |
404 | ||
18f705f4 | 405 | config TASK_XACCT |
19c92399 | 406 | bool "Enable extended accounting over taskstats" |
18f705f4 AD |
407 | depends on TASKSTATS |
408 | help | |
409 | Collect extended task accounting data and send the data | |
410 | to userland for processing over the taskstats interface. | |
411 | ||
412 | Say N if unsure. | |
413 | ||
414 | config TASK_IO_ACCOUNTING | |
19c92399 | 415 | bool "Enable per-task storage I/O accounting" |
18f705f4 AD |
416 | depends on TASK_XACCT |
417 | help | |
418 | Collect information on the number of bytes of storage I/O which this | |
419 | task has caused. | |
420 | ||
421 | Say N if unsure. | |
422 | ||
391dc69c | 423 | endmenu # "CPU/Task time and stats accounting" |
d9817ebe | 424 | |
c903ff83 MT |
425 | menu "RCU Subsystem" |
426 | ||
427 | choice | |
428 | prompt "RCU Implementation" | |
31c9a24e | 429 | default TREE_RCU |
c903ff83 | 430 | |
c903ff83 MT |
431 | config TREE_RCU |
432 | bool "Tree-based hierarchical RCU" | |
687d7a96 | 433 | depends on !PREEMPT && SMP |
016a8d5b | 434 | select IRQ_WORK |
c903ff83 MT |
435 | help |
436 | This option selects the RCU implementation that is | |
437 | designed for very large SMP system with hundreds or | |
c17ef453 PM |
438 | thousands of CPUs. It also scales down nicely to |
439 | smaller systems. | |
c903ff83 | 440 | |
f41d911f | 441 | config TREE_PREEMPT_RCU |
a57eb940 | 442 | bool "Preemptible tree-based hierarchical RCU" |
9fc52d83 | 443 | depends on PREEMPT |
f41d911f PM |
444 | help |
445 | This option selects the RCU implementation that is | |
446 | designed for very large SMP systems with hundreds or | |
447 | thousands of CPUs, but for which real-time response | |
bbe3eae8 PM |
448 | is also required. It also scales down nicely to |
449 | smaller systems. | |
f41d911f | 450 | |
9fc52d83 PM |
451 | Select this option if you are unsure. |
452 | ||
9b1d82fa PM |
453 | config TINY_RCU |
454 | bool "UP-only small-memory-footprint RCU" | |
8008e129 | 455 | depends on !PREEMPT && !SMP |
9b1d82fa PM |
456 | help |
457 | This option selects the RCU implementation that is | |
458 | designed for UP systems from which real-time response | |
459 | is not required. This option greatly reduces the | |
460 | memory footprint of RCU. | |
461 | ||
a57eb940 PM |
462 | config TINY_PREEMPT_RCU |
463 | bool "Preemptible UP-only small-memory-footprint RCU" | |
8008e129 | 464 | depends on PREEMPT && !SMP |
a57eb940 PM |
465 | help |
466 | This option selects the RCU implementation that is designed | |
467 | for real-time UP systems. This option greatly reduces the | |
468 | memory footprint of RCU. | |
469 | ||
c903ff83 MT |
470 | endchoice |
471 | ||
a57eb940 PM |
472 | config PREEMPT_RCU |
473 | def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) | |
474 | help | |
475 | This option enables preemptible-RCU code that is common between | |
476 | the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. | |
477 | ||
6bfc09e2 PM |
478 | config RCU_STALL_COMMON |
479 | def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE ) | |
480 | help | |
481 | This option enables RCU CPU stall code that is common between | |
482 | the TINY and TREE variants of RCU. The purpose is to allow | |
483 | the tiny variants to disable RCU CPU stall warnings, while | |
484 | making these warnings mandatory for the tree variants. | |
485 | ||
91d1aa43 FW |
486 | config CONTEXT_TRACKING |
487 | bool | |
488 | ||
2b1d5024 FW |
489 | config RCU_USER_QS |
490 | bool "Consider userspace as in RCU extended quiescent state" | |
91d1aa43 FW |
491 | depends on HAVE_CONTEXT_TRACKING && SMP |
492 | select CONTEXT_TRACKING | |
2b1d5024 FW |
493 | help |
494 | This option sets hooks on kernel / userspace boundaries and | |
495 | puts RCU in extended quiescent state when the CPU runs in | |
496 | userspace. It means that when a CPU runs in userspace, it is | |
497 | excluded from the global RCU state machine and thus doesn't | |
af71befa | 498 | try to keep the timer tick on for RCU. |
2b1d5024 | 499 | |
d677124b | 500 | Unless you want to hack and help the development of the full |
91d1aa43 | 501 | dynticks mode, you shouldn't enable this option. It also |
af71befa | 502 | adds unnecessary overhead. |
d677124b FW |
503 | |
504 | If unsure say N | |
505 | ||
91d1aa43 FW |
506 | config CONTEXT_TRACKING_FORCE |
507 | bool "Force context tracking" | |
508 | depends on CONTEXT_TRACKING | |
8b438766 | 509 | default CONTEXT_TRACKING |
1fd2b442 | 510 | help |
91d1aa43 FW |
511 | Probe on user/kernel boundaries by default in order to |
512 | test the features that rely on it such as userspace RCU extended | |
513 | quiescent states. | |
514 | This test is there for debugging until we have a real user like the | |
515 | full dynticks mode. | |
d677124b | 516 | |
c903ff83 MT |
517 | config RCU_FANOUT |
518 | int "Tree-based hierarchical RCU fanout value" | |
519 | range 2 64 if 64BIT | |
520 | range 2 32 if !64BIT | |
f41d911f | 521 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
522 | default 64 if 64BIT |
523 | default 32 if !64BIT | |
524 | help | |
525 | This option controls the fanout of hierarchical implementations | |
526 | of RCU, allowing RCU to work efficiently on machines with | |
4d87ffad PM |
527 | large numbers of CPUs. This value must be at least the fourth |
528 | root of NR_CPUS, which allows NR_CPUS to be insanely large. | |
529 | The default value of RCU_FANOUT should be used for production | |
530 | systems, but if you are stress-testing the RCU implementation | |
531 | itself, small RCU_FANOUT values allow you to test large-system | |
532 | code paths on small(er) systems. | |
c903ff83 MT |
533 | |
534 | Select a specific number if testing RCU itself. | |
535 | Take the default if unsure. | |
536 | ||
8932a63d PM |
537 | config RCU_FANOUT_LEAF |
538 | int "Tree-based hierarchical RCU leaf-level fanout value" | |
539 | range 2 RCU_FANOUT if 64BIT | |
540 | range 2 RCU_FANOUT if !64BIT | |
541 | depends on TREE_RCU || TREE_PREEMPT_RCU | |
542 | default 16 | |
543 | help | |
544 | This option controls the leaf-level fanout of hierarchical | |
545 | implementations of RCU, and allows trading off cache misses | |
546 | against lock contention. Systems that synchronize their | |
547 | scheduling-clock interrupts for energy-efficiency reasons will | |
548 | want the default because the smaller leaf-level fanout keeps | |
549 | lock contention levels acceptably low. Very large systems | |
550 | (hundreds or thousands of CPUs) will instead want to set this | |
551 | value to the maximum value possible in order to reduce the | |
552 | number of cache misses incurred during RCU's grace-period | |
553 | initialization. These systems tend to run CPU-bound, and thus | |
554 | are not helped by synchronized interrupts, and thus tend to | |
555 | skew them, which reduces lock contention enough that large | |
556 | leaf-level fanouts work well. | |
557 | ||
558 | Select a specific number if testing RCU itself. | |
559 | ||
560 | Select the maximum permissible value for large systems. | |
561 | ||
562 | Take the default if unsure. | |
563 | ||
c903ff83 MT |
564 | config RCU_FANOUT_EXACT |
565 | bool "Disable tree-based hierarchical RCU auto-balancing" | |
f41d911f | 566 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
567 | default n |
568 | help | |
569 | This option forces use of the exact RCU_FANOUT value specified, | |
570 | regardless of imbalances in the hierarchy. This is useful for | |
571 | testing RCU itself, and might one day be useful on systems with | |
572 | strong NUMA behavior. | |
573 | ||
574 | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. | |
575 | ||
576 | Say N if unsure. | |
577 | ||
8bd93a2c PM |
578 | config RCU_FAST_NO_HZ |
579 | bool "Accelerate last non-dyntick-idle CPU's grace periods" | |
3451d024 | 580 | depends on NO_HZ_COMMON && SMP |
8bd93a2c PM |
581 | default n |
582 | help | |
c0f4dfd4 PM |
583 | This option permits CPUs to enter dynticks-idle state even if |
584 | they have RCU callbacks queued, and prevents RCU from waking | |
585 | these CPUs up more than roughly once every four jiffies (by | |
586 | default, you can adjust this using the rcutree.rcu_idle_gp_delay | |
587 | parameter), thus improving energy efficiency. On the other | |
588 | hand, this option increases the duration of RCU grace periods, | |
589 | for example, slowing down synchronize_rcu(). | |
ba49df47 | 590 | |
c0f4dfd4 PM |
591 | Say Y if energy efficiency is critically important, and you |
592 | don't care about increased grace-period durations. | |
8bd93a2c PM |
593 | |
594 | Say N if you are unsure. | |
595 | ||
c903ff83 | 596 | config TREE_RCU_TRACE |
f41d911f | 597 | def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) |
c903ff83 MT |
598 | select DEBUG_FS |
599 | help | |
f41d911f PM |
600 | This option provides tracing for the TREE_RCU and |
601 | TREE_PREEMPT_RCU implementations, permitting Makefile to | |
602 | trivially select kernel/rcutree_trace.c. | |
c903ff83 | 603 | |
24278d14 PM |
604 | config RCU_BOOST |
605 | bool "Enable RCU priority boosting" | |
27f4d280 | 606 | depends on RT_MUTEXES && PREEMPT_RCU |
24278d14 PM |
607 | default n |
608 | help | |
609 | This option boosts the priority of preempted RCU readers that | |
610 | block the current preemptible RCU grace period for too long. | |
611 | This option also prevents heavy loads from blocking RCU | |
612 | callback invocation for all flavors of RCU. | |
613 | ||
614 | Say Y here if you are working with real-time apps or heavy loads | |
615 | Say N here if you are unsure. | |
616 | ||
617 | config RCU_BOOST_PRIO | |
618 | int "Real-time priority to boost RCU readers to" | |
619 | range 1 99 | |
620 | depends on RCU_BOOST | |
621 | default 1 | |
622 | help | |
c9336643 PM |
623 | This option specifies the real-time priority to which long-term |
624 | preempted RCU readers are to be boosted. If you are working | |
625 | with a real-time application that has one or more CPU-bound | |
626 | threads running at a real-time priority level, you should set | |
627 | RCU_BOOST_PRIO to a priority higher then the highest-priority | |
628 | real-time CPU-bound thread. The default RCU_BOOST_PRIO value | |
629 | of 1 is appropriate in the common case, which is real-time | |
630 | applications that do not have any CPU-bound threads. | |
631 | ||
632 | Some real-time applications might not have a single real-time | |
633 | thread that saturates a given CPU, but instead might have | |
634 | multiple real-time threads that, taken together, fully utilize | |
635 | that CPU. In this case, you should set RCU_BOOST_PRIO to | |
636 | a priority higher than the lowest-priority thread that is | |
637 | conspiring to prevent the CPU from running any non-real-time | |
638 | tasks. For example, if one thread at priority 10 and another | |
639 | thread at priority 5 are between themselves fully consuming | |
640 | the CPU time on a given CPU, then RCU_BOOST_PRIO should be | |
641 | set to priority 6 or higher. | |
24278d14 PM |
642 | |
643 | Specify the real-time priority, or take the default if unsure. | |
644 | ||
645 | config RCU_BOOST_DELAY | |
646 | int "Milliseconds to delay boosting after RCU grace-period start" | |
647 | range 0 3000 | |
648 | depends on RCU_BOOST | |
649 | default 500 | |
650 | help | |
651 | This option specifies the time to wait after the beginning of | |
652 | a given grace period before priority-boosting preempted RCU | |
653 | readers blocking that grace period. Note that any RCU reader | |
654 | blocking an expedited RCU grace period is boosted immediately. | |
655 | ||
656 | Accept the default if unsure. | |
657 | ||
3fbfbf7a | 658 | config RCU_NOCB_CPU |
34ed6246 | 659 | bool "Offload RCU callback processing from boot-selected CPUs (EXPERIMENTAL" |
3fbfbf7a PM |
660 | depends on TREE_RCU || TREE_PREEMPT_RCU |
661 | default n | |
662 | help | |
663 | Use this option to reduce OS jitter for aggressive HPC or | |
664 | real-time workloads. It can also be used to offload RCU | |
665 | callback invocation to energy-efficient CPUs in battery-powered | |
666 | asymmetric multiprocessors. | |
667 | ||
668 | This option offloads callback invocation from the set of | |
669 | CPUs specified at boot time by the rcu_nocbs parameter. | |
a4889858 PM |
670 | For each such CPU, a kthread ("rcuox/N") will be created to |
671 | invoke callbacks, where the "N" is the CPU being offloaded, | |
672 | and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and | |
673 | "s" for RCU-sched. Nothing prevents this kthread from running | |
674 | on the specified CPUs, but (1) the kthreads may be preempted | |
675 | between each callback, and (2) affinity or cgroups can be used | |
676 | to force the kthreads to run on whatever set of CPUs is desired. | |
3fbfbf7a | 677 | |
34ed6246 | 678 | Say Y here if you want to help to debug reduced OS jitter. |
3fbfbf7a PM |
679 | Say N here if you are unsure. |
680 | ||
911af505 PM |
681 | choice |
682 | prompt "Build-forced no-CBs CPUs" | |
683 | default RCU_NOCB_CPU_NONE | |
684 | help | |
685 | This option allows no-CBs CPUs to be specified at build time. | |
686 | Additional no-CBs CPUs may be specified by the rcu_nocbs= | |
687 | boot parameter. | |
688 | ||
689 | config RCU_NOCB_CPU_NONE | |
690 | bool "No build_forced no-CBs CPUs" | |
73c30828 | 691 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
911af505 PM |
692 | help |
693 | This option does not force any of the CPUs to be no-CBs CPUs. | |
694 | Only CPUs designated by the rcu_nocbs= boot parameter will be | |
695 | no-CBs CPUs. | |
696 | ||
697 | config RCU_NOCB_CPU_ZERO | |
698 | bool "CPU 0 is a build_forced no-CBs CPU" | |
73c30828 | 699 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
911af505 PM |
700 | help |
701 | This option forces CPU 0 to be a no-CBs CPU. Additional CPUs | |
702 | may be designated as no-CBs CPUs using the rcu_nocbs= boot | |
703 | parameter will be no-CBs CPUs. | |
704 | ||
705 | Select this if CPU 0 needs to be a no-CBs CPU for real-time | |
706 | or energy-efficiency reasons. | |
707 | ||
708 | config RCU_NOCB_CPU_ALL | |
709 | bool "All CPUs are build_forced no-CBs CPUs" | |
710 | depends on RCU_NOCB_CPU | |
711 | help | |
712 | This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= | |
713 | boot parameter will be ignored. | |
714 | ||
715 | Select this if all CPUs need to be no-CBs CPUs for real-time | |
716 | or energy-efficiency reasons. | |
717 | ||
718 | endchoice | |
719 | ||
c903ff83 MT |
720 | endmenu # "RCU Subsystem" |
721 | ||
1da177e4 | 722 | config IKCONFIG |
f2443ab6 | 723 | tristate "Kernel .config support" |
1da177e4 LT |
724 | ---help--- |
725 | This option enables the complete Linux kernel ".config" file | |
726 | contents to be saved in the kernel. It provides documentation | |
727 | of which kernel options are used in a running kernel or in an | |
728 | on-disk kernel. This information can be extracted from the kernel | |
729 | image file with the script scripts/extract-ikconfig and used as | |
730 | input to rebuild the current kernel or to build another kernel. | |
731 | It can also be extracted from a running kernel by reading | |
732 | /proc/config.gz if enabled (below). | |
733 | ||
734 | config IKCONFIG_PROC | |
735 | bool "Enable access to .config through /proc/config.gz" | |
736 | depends on IKCONFIG && PROC_FS | |
737 | ---help--- | |
738 | This option enables access to the kernel configuration file | |
739 | through /proc/config.gz. | |
740 | ||
794543a2 AJS |
741 | config LOG_BUF_SHIFT |
742 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | |
743 | range 12 21 | |
f17a32e9 | 744 | default 17 |
794543a2 AJS |
745 | help |
746 | Select kernel log buffer size as a power of 2. | |
f17a32e9 AB |
747 | Examples: |
748 | 17 => 128 KB | |
749 | 16 => 64 KB | |
750 | 15 => 32 KB | |
751 | 14 => 16 KB | |
794543a2 AJS |
752 | 13 => 8 KB |
753 | 12 => 4 KB | |
754 | ||
a5574cf6 IM |
755 | # |
756 | # Architectures with an unreliable sched_clock() should select this: | |
757 | # | |
758 | config HAVE_UNSTABLE_SCHED_CLOCK | |
759 | bool | |
760 | ||
be3a7284 AA |
761 | # |
762 | # For architectures that want to enable the support for NUMA-affine scheduler | |
763 | # balancing logic: | |
764 | # | |
765 | config ARCH_SUPPORTS_NUMA_BALANCING | |
766 | bool | |
767 | ||
768 | # For architectures that (ab)use NUMA to represent different memory regions | |
769 | # all cpu-local but of different latencies, such as SuperH. | |
770 | # | |
771 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
772 | bool | |
773 | ||
774 | # | |
775 | # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE | |
776 | config ARCH_WANTS_PROT_NUMA_PROT_NONE | |
777 | bool | |
778 | ||
779 | config ARCH_USES_NUMA_PROT_NONE | |
780 | bool | |
781 | default y | |
782 | depends on ARCH_WANTS_PROT_NUMA_PROT_NONE | |
783 | depends on NUMA_BALANCING | |
784 | ||
1a687c2e MG |
785 | config NUMA_BALANCING_DEFAULT_ENABLED |
786 | bool "Automatically enable NUMA aware memory/task placement" | |
787 | default y | |
788 | depends on NUMA_BALANCING | |
789 | help | |
790 | If set, autonumic NUMA balancing will be enabled if running on a NUMA | |
791 | machine. | |
792 | ||
be3a7284 AA |
793 | config NUMA_BALANCING |
794 | bool "Memory placement aware NUMA scheduler" | |
be3a7284 AA |
795 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
796 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
797 | depends on SMP && NUMA && MIGRATION | |
798 | help | |
799 | This option adds support for automatic NUMA aware memory/task placement. | |
800 | The mechanism is quite primitive and is based on migrating memory when | |
801 | it is references to the node the task is running on. | |
802 | ||
803 | This system will be inactive on UMA systems. | |
804 | ||
23964d2d LZ |
805 | menuconfig CGROUPS |
806 | boolean "Control Group support" | |
0dea1168 | 807 | depends on EVENTFD |
5cdc38f9 | 808 | help |
23964d2d | 809 | This option adds support for grouping sets of processes together, for |
5cdc38f9 KH |
810 | use with process control subsystems such as Cpusets, CFS, memory |
811 | controls or device isolation. | |
812 | See | |
5cdc38f9 | 813 | - Documentation/scheduler/sched-design-CFS.txt (CFS) |
45ce80fb LZ |
814 | - Documentation/cgroups/ (features for grouping, isolation |
815 | and resource control) | |
5cdc38f9 KH |
816 | |
817 | Say N if unsure. | |
818 | ||
23964d2d LZ |
819 | if CGROUPS |
820 | ||
5cdc38f9 KH |
821 | config CGROUP_DEBUG |
822 | bool "Example debug cgroup subsystem" | |
5cdc38f9 KH |
823 | default n |
824 | help | |
825 | This option enables a simple cgroup subsystem that | |
826 | exports useful debugging information about the cgroups | |
23964d2d | 827 | framework. |
5cdc38f9 | 828 | |
23964d2d | 829 | Say N if unsure. |
5cdc38f9 | 830 | |
5cdc38f9 | 831 | config CGROUP_FREEZER |
23964d2d | 832 | bool "Freezer cgroup subsystem" |
23964d2d LZ |
833 | help |
834 | Provides a way to freeze and unfreeze all tasks in a | |
5cdc38f9 KH |
835 | cgroup. |
836 | ||
837 | config CGROUP_DEVICE | |
838 | bool "Device controller for cgroups" | |
5cdc38f9 KH |
839 | help |
840 | Provides a cgroup implementing whitelists for devices which | |
841 | a process in the cgroup can mknod or open. | |
842 | ||
843 | config CPUSETS | |
844 | bool "Cpuset support" | |
5cdc38f9 KH |
845 | help |
846 | This option will let you create and manage CPUSETs which | |
847 | allow dynamically partitioning a system into sets of CPUs and | |
848 | Memory Nodes and assigning tasks to run only within those sets. | |
849 | This is primarily useful on large SMP or NUMA systems. | |
850 | ||
851 | Say N if unsure. | |
852 | ||
23964d2d LZ |
853 | config PROC_PID_CPUSET |
854 | bool "Include legacy /proc/<pid>/cpuset file" | |
855 | depends on CPUSETS | |
856 | default y | |
857 | ||
d842de87 SV |
858 | config CGROUP_CPUACCT |
859 | bool "Simple CPU accounting cgroup subsystem" | |
d842de87 SV |
860 | help |
861 | Provides a simple Resource Controller for monitoring the | |
23964d2d | 862 | total CPU consumed by the tasks in a cgroup. |
d842de87 | 863 | |
e552b661 PE |
864 | config RESOURCE_COUNTERS |
865 | bool "Resource counters" | |
866 | help | |
867 | This option enables controller independent resource accounting | |
23964d2d | 868 | infrastructure that works with cgroups. |
e552b661 | 869 | |
c255a458 | 870 | config MEMCG |
00f0b825 | 871 | bool "Memory Resource Controller for Control Groups" |
79ae9c29 | 872 | depends on RESOURCE_COUNTERS |
cf475ad2 | 873 | select MM_OWNER |
00f0b825 | 874 | help |
84ad6d70 | 875 | Provides a memory resource controller that manages both anonymous |
21acb9ca | 876 | memory and page cache. (See Documentation/cgroups/memory.txt) |
00f0b825 BS |
877 | |
878 | Note that setting this option increases fixed memory overhead | |
84ad6d70 KH |
879 | associated with each page of memory in the system. By this, |
880 | 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory | |
881 | usage tracking struct at boot. Total amount of this is printed out | |
882 | at boot. | |
00f0b825 BS |
883 | |
884 | Only enable when you're ok with these trade offs and really | |
84ad6d70 KH |
885 | sure you need the memory resource controller. Even when you enable |
886 | this, you can set "cgroup_disable=memory" at your boot option to | |
887 | disable memory resource controller and you can avoid overheads. | |
c9d5409f | 888 | (and lose benefits of memory resource controller) |
00f0b825 | 889 | |
cf475ad2 BS |
890 | This config option also selects MM_OWNER config option, which |
891 | could in turn add some fork/exit overhead. | |
892 | ||
c255a458 | 893 | config MEMCG_SWAP |
65e0e811 | 894 | bool "Memory Resource Controller Swap Extension" |
c255a458 | 895 | depends on MEMCG && SWAP |
c077719b KH |
896 | help |
897 | Add swap management feature to memory resource controller. When you | |
898 | enable this, you can limit mem+swap usage per cgroup. In other words, | |
899 | when you disable this, memory resource controller has no cares to | |
900 | usage of swap...a process can exhaust all of the swap. This extension | |
901 | is useful when you want to avoid exhaustion swap but this itself | |
902 | adds more overheads and consumes memory for remembering information. | |
903 | Especially if you use 32bit system or small memory system, please | |
904 | be careful about enabling this. When memory resource controller | |
905 | is disabled by boot option, this will be automatically disabled and | |
906 | there will be no overhead from this. Even when you set this config=y, | |
00a66d29 | 907 | if boot option "swapaccount=0" is set, swap will not be accounted. |
627991a2 KH |
908 | Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page |
909 | size is 4096bytes, 512k per 1Gbytes of swap. | |
c255a458 | 910 | config MEMCG_SWAP_ENABLED |
a42c390c | 911 | bool "Memory Resource Controller Swap Extension enabled by default" |
c255a458 | 912 | depends on MEMCG_SWAP |
a42c390c MH |
913 | default y |
914 | help | |
915 | Memory Resource Controller Swap Extension comes with its price in | |
916 | a bigger memory consumption. General purpose distribution kernels | |
43d547f9 | 917 | which want to enable the feature but keep it disabled by default |
a42c390c MH |
918 | and let the user enable it by swapaccount boot command line |
919 | parameter should have this option unselected. | |
920 | For those who want to have the feature enabled by default should | |
921 | select this option (if, for some reason, they need to disable it | |
00a66d29 | 922 | then swapaccount=0 does the trick). |
c255a458 | 923 | config MEMCG_KMEM |
19c92399 KC |
924 | bool "Memory Resource Controller Kernel Memory accounting" |
925 | depends on MEMCG | |
510fc4e1 | 926 | depends on SLUB || SLAB |
e5671dfa GC |
927 | help |
928 | The Kernel Memory extension for Memory Resource Controller can limit | |
929 | the amount of memory used by kernel objects in the system. Those are | |
930 | fundamentally different from the entities handled by the standard | |
931 | Memory Controller, which are page-based, and can be swapped. Users of | |
932 | the kmem extension can use it to guarantee that no group of processes | |
933 | will ever exhaust kernel resources alone. | |
c077719b | 934 | |
2bc64a20 AK |
935 | config CGROUP_HUGETLB |
936 | bool "HugeTLB Resource Controller for Control Groups" | |
19c92399 | 937 | depends on RESOURCE_COUNTERS && HUGETLB_PAGE |
2bc64a20 AK |
938 | default n |
939 | help | |
940 | Provides a cgroup Resource Controller for HugeTLB pages. | |
941 | When you enable this, you can put a per cgroup limit on HugeTLB usage. | |
942 | The limit is enforced during page fault. Since HugeTLB doesn't | |
943 | support page reclaim, enforcing the limit at page fault time implies | |
944 | that, the application will get SIGBUS signal if it tries to access | |
945 | HugeTLB pages beyond its limit. This requires the application to know | |
946 | beforehand how much HugeTLB pages it would require for its use. The | |
947 | control group is tracked in the third page lru pointer. This means | |
948 | that we cannot use the controller with huge page less than 3 pages. | |
949 | ||
e5d1367f SE |
950 | config CGROUP_PERF |
951 | bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" | |
952 | depends on PERF_EVENTS && CGROUPS | |
953 | help | |
954 | This option extends the per-cpu mode to restrict monitoring to | |
2d0f2520 | 955 | threads which belong to the cgroup specified and run on the |
e5d1367f SE |
956 | designated cpu. |
957 | ||
958 | Say N if unsure. | |
959 | ||
7c941438 DG |
960 | menuconfig CGROUP_SCHED |
961 | bool "Group CPU scheduler" | |
7c941438 DG |
962 | default n |
963 | help | |
964 | This feature lets CPU scheduler recognize task groups and control CPU | |
965 | bandwidth allocation to such task groups. It uses cgroups to group | |
966 | tasks. | |
967 | ||
968 | if CGROUP_SCHED | |
969 | config FAIR_GROUP_SCHED | |
970 | bool "Group scheduling for SCHED_OTHER" | |
971 | depends on CGROUP_SCHED | |
972 | default CGROUP_SCHED | |
973 | ||
ab84d31e PT |
974 | config CFS_BANDWIDTH |
975 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" | |
ab84d31e PT |
976 | depends on FAIR_GROUP_SCHED |
977 | default n | |
978 | help | |
979 | This option allows users to define CPU bandwidth rates (limits) for | |
980 | tasks running within the fair group scheduler. Groups with no limit | |
981 | set are considered to be unconstrained and will run with no | |
982 | restriction. | |
983 | See tip/Documentation/scheduler/sched-bwc.txt for more information. | |
984 | ||
7c941438 DG |
985 | config RT_GROUP_SCHED |
986 | bool "Group scheduling for SCHED_RR/FIFO" | |
7c941438 DG |
987 | depends on CGROUP_SCHED |
988 | default n | |
989 | help | |
990 | This feature lets you explicitly allocate real CPU bandwidth | |
32bd7eb5 | 991 | to task groups. If enabled, it will also make it impossible to |
7c941438 DG |
992 | schedule realtime tasks for non-root users until you allocate |
993 | realtime bandwidth for them. | |
994 | See Documentation/scheduler/sched-rt-group.txt for more information. | |
995 | ||
996 | endif #CGROUP_SCHED | |
997 | ||
afc24d49 | 998 | config BLK_CGROUP |
32e380ae | 999 | bool "Block IO controller" |
79ae9c29 | 1000 | depends on BLOCK |
afc24d49 VG |
1001 | default n |
1002 | ---help--- | |
1003 | Generic block IO controller cgroup interface. This is the common | |
1004 | cgroup interface which should be used by various IO controlling | |
1005 | policies. | |
1006 | ||
1007 | Currently, CFQ IO scheduler uses it to recognize task groups and | |
1008 | control disk bandwidth allocation (proportional time slice allocation) | |
e43473b7 VG |
1009 | to such task groups. It is also used by bio throttling logic in |
1010 | block layer to implement upper limit in IO rates on a device. | |
afc24d49 VG |
1011 | |
1012 | This option only enables generic Block IO controller infrastructure. | |
e43473b7 | 1013 | One needs to also enable actual IO controlling logic/policy. For |
79e2e759 MW |
1014 | enabling proportional weight division of disk bandwidth in CFQ, set |
1015 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set | |
c5e0591a | 1016 | CONFIG_BLK_DEV_THROTTLING=y. |
afc24d49 VG |
1017 | |
1018 | See Documentation/cgroups/blkio-controller.txt for more information. | |
1019 | ||
1020 | config DEBUG_BLK_CGROUP | |
1021 | bool "Enable Block IO controller debugging" | |
1022 | depends on BLK_CGROUP | |
1023 | default n | |
1024 | ---help--- | |
1025 | Enable some debugging help. Currently it exports additional stat | |
1026 | files in a cgroup which can be useful for debugging. | |
1027 | ||
23964d2d | 1028 | endif # CGROUPS |
c077719b | 1029 | |
067bce1a CG |
1030 | config CHECKPOINT_RESTORE |
1031 | bool "Checkpoint/restore support" if EXPERT | |
1032 | default n | |
1033 | help | |
1034 | Enables additional kernel features in a sake of checkpoint/restore. | |
1035 | In particular it adds auxiliary prctl codes to setup process text, | |
1036 | data and heap segment sizes, and a few additional /proc filesystem | |
1037 | entries. | |
1038 | ||
1039 | If unsure, say N here. | |
1040 | ||
8dd2a82c | 1041 | menuconfig NAMESPACES |
6a108a14 DR |
1042 | bool "Namespaces support" if EXPERT |
1043 | default !EXPERT | |
c5289a69 PE |
1044 | help |
1045 | Provides the way to make tasks work with different objects using | |
1046 | the same id. For example same IPC id may refer to different objects | |
1047 | or same user id or pid may refer to different tasks when used in | |
1048 | different namespaces. | |
1049 | ||
8dd2a82c DL |
1050 | if NAMESPACES |
1051 | ||
58bfdd6d PE |
1052 | config UTS_NS |
1053 | bool "UTS namespace" | |
17a6d441 | 1054 | default y |
58bfdd6d PE |
1055 | help |
1056 | In this namespace tasks see different info provided with the | |
1057 | uname() system call | |
1058 | ||
ae5e1b22 PE |
1059 | config IPC_NS |
1060 | bool "IPC namespace" | |
8dd2a82c | 1061 | depends on (SYSVIPC || POSIX_MQUEUE) |
17a6d441 | 1062 | default y |
ae5e1b22 PE |
1063 | help |
1064 | In this namespace tasks work with IPC ids which correspond to | |
614b84cf | 1065 | different IPC objects in different namespaces. |
ae5e1b22 | 1066 | |
aee16ce7 | 1067 | config USER_NS |
19c92399 | 1068 | bool "User namespace" |
e1c972b6 | 1069 | depends on UIDGID_CONVERTED |
5673a94c | 1070 | select UIDGID_STRICT_TYPE_CHECKS |
e1c972b6 | 1071 | |
5673a94c | 1072 | default n |
aee16ce7 PE |
1073 | help |
1074 | This allows containers, i.e. vservers, to use user namespaces | |
1075 | to provide different user info for different servers. | |
e11f0ae3 EB |
1076 | |
1077 | When user namespaces are enabled in the kernel it is | |
1078 | recommended that the MEMCG and MEMCG_KMEM options also be | |
1079 | enabled and that user-space use the memory control groups to | |
1080 | limit the amount of memory a memory unprivileged users can | |
1081 | use. | |
1082 | ||
aee16ce7 PE |
1083 | If unsure, say N. |
1084 | ||
74bd59bb | 1085 | config PID_NS |
9bd38c2c | 1086 | bool "PID Namespaces" |
17a6d441 | 1087 | default y |
74bd59bb | 1088 | help |
12d2b8f9 | 1089 | Support process id namespaces. This allows having multiple |
692105b8 | 1090 | processes with the same pid as long as they are in different |
74bd59bb PE |
1091 | pid namespaces. This is a building block of containers. |
1092 | ||
d6eb633f MH |
1093 | config NET_NS |
1094 | bool "Network namespace" | |
8dd2a82c | 1095 | depends on NET |
17a6d441 | 1096 | default y |
d6eb633f MH |
1097 | help |
1098 | Allow user space to create what appear to be multiple instances | |
1099 | of the network stack. | |
1100 | ||
8dd2a82c DL |
1101 | endif # NAMESPACES |
1102 | ||
e1c972b6 EB |
1103 | config UIDGID_CONVERTED |
1104 | # True if all of the selected software conmponents are known | |
1105 | # to have uid_t and gid_t converted to kuid_t and kgid_t | |
1106 | # where appropriate and are otherwise safe to use with | |
1107 | # the user namespace. | |
1108 | bool | |
1109 | default y | |
1110 | ||
e1c972b6 | 1111 | # Filesystems |
e1c972b6 EB |
1112 | depends on XFS_FS = n |
1113 | ||
5673a94c EB |
1114 | config UIDGID_STRICT_TYPE_CHECKS |
1115 | bool "Require conversions between uid/gids and their internal representation" | |
e1c972b6 | 1116 | depends on UIDGID_CONVERTED |
5673a94c EB |
1117 | default n |
1118 | help | |
1119 | While the nececessary conversions are being added to all subsystems this option allows | |
1120 | the code to continue to build for unconverted subsystems. | |
1121 | ||
1122 | Say Y here if you want the strict type checking enabled | |
1123 | ||
5091faa4 MG |
1124 | config SCHED_AUTOGROUP |
1125 | bool "Automatic process group scheduling" | |
1126 | select EVENTFD | |
1127 | select CGROUPS | |
1128 | select CGROUP_SCHED | |
1129 | select FAIR_GROUP_SCHED | |
1130 | help | |
1131 | This option optimizes the scheduler for common desktop workloads by | |
1132 | automatically creating and populating task groups. This separation | |
1133 | of workloads isolates aggressive CPU burners (like build jobs) from | |
1134 | desktop applications. Task group autogeneration is currently based | |
1135 | upon task session. | |
1136 | ||
7af37bec DL |
1137 | config MM_OWNER |
1138 | bool | |
1139 | ||
1140 | config SYSFS_DEPRECATED | |
5d6a4ea5 | 1141 | bool "Enable deprecated sysfs features to support old userspace tools" |
7af37bec DL |
1142 | depends on SYSFS |
1143 | default n | |
1144 | help | |
1145 | This option adds code that switches the layout of the "block" class | |
1146 | devices, to not show up in /sys/class/block/, but only in | |
1147 | /sys/block/. | |
1148 | ||
1149 | This switch is only active when the sysfs.deprecated=1 boot option is | |
1150 | passed or the SYSFS_DEPRECATED_V2 option is set. | |
1151 | ||
1152 | This option allows new kernels to run on old distributions and tools, | |
1153 | which might get confused by /sys/class/block/. Since 2007/2008 all | |
1154 | major distributions and tools handle this just fine. | |
1155 | ||
1156 | Recent distributions and userspace tools after 2009/2010 depend on | |
1157 | the existence of /sys/class/block/, and will not work with this | |
1158 | option enabled. | |
1159 | ||
1160 | Only if you are using a new kernel on an old distribution, you might | |
1161 | need to say Y here. | |
1162 | ||
1163 | config SYSFS_DEPRECATED_V2 | |
5d6a4ea5 | 1164 | bool "Enable deprecated sysfs features by default" |
7af37bec DL |
1165 | default n |
1166 | depends on SYSFS | |
1167 | depends on SYSFS_DEPRECATED | |
1168 | help | |
1169 | Enable deprecated sysfs by default. | |
1170 | ||
1171 | See the CONFIG_SYSFS_DEPRECATED option for more details about this | |
1172 | option. | |
1173 | ||
1174 | Only if you are using a new kernel on an old distribution, you might | |
1175 | need to say Y here. Even then, odds are you would not need it | |
1176 | enabled, you can always pass the boot option if absolutely necessary. | |
1177 | ||
1178 | config RELAY | |
1179 | bool "Kernel->user space relay support (formerly relayfs)" | |
1180 | help | |
1181 | This option enables support for relay interface support in | |
1182 | certain file systems (such as debugfs). | |
1183 | It is designed to provide an efficient mechanism for tools and | |
1184 | facilities to relay large amounts of data from kernel space to | |
1185 | user space. | |
1186 | ||
1187 | If unsure, say N. | |
1188 | ||
f991633d DG |
1189 | config BLK_DEV_INITRD |
1190 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | |
1191 | depends on BROKEN || !FRV | |
1192 | help | |
1193 | The initial RAM filesystem is a ramfs which is loaded by the | |
1194 | boot loader (loadlin or lilo) and that is mounted as root | |
1195 | before the normal boot procedure. It is typically used to | |
1196 | load modules needed to mount the "real" root file system, | |
1197 | etc. See <file:Documentation/initrd.txt> for details. | |
1198 | ||
1199 | If RAM disk support (BLK_DEV_RAM) is also included, this | |
1200 | also enables initial RAM disk (initrd) support and adds | |
1201 | 15 Kbytes (more on some other architectures) to the kernel size. | |
1202 | ||
1203 | If unsure say Y. | |
1204 | ||
c33df4ea JPS |
1205 | if BLK_DEV_INITRD |
1206 | ||
dbec4866 SR |
1207 | source "usr/Kconfig" |
1208 | ||
c33df4ea JPS |
1209 | endif |
1210 | ||
c45b4f1f | 1211 | config CC_OPTIMIZE_FOR_SIZE |
96fffeb4 | 1212 | bool "Optimize for size" |
c45b4f1f LT |
1213 | help |
1214 | Enabling this option will pass "-Os" instead of "-O2" to gcc | |
1215 | resulting in a smaller kernel. | |
1216 | ||
3a55fb0d | 1217 | If unsure, say N. |
c45b4f1f | 1218 | |
0847062a RD |
1219 | config SYSCTL |
1220 | bool | |
1221 | ||
b943c460 RD |
1222 | config ANON_INODES |
1223 | bool | |
1224 | ||
657a5209 MF |
1225 | config HAVE_UID16 |
1226 | bool | |
1227 | ||
1228 | config SYSCTL_EXCEPTION_TRACE | |
1229 | bool | |
1230 | help | |
1231 | Enable support for /proc/sys/debug/exception-trace. | |
1232 | ||
1233 | config SYSCTL_ARCH_UNALIGN_NO_WARN | |
1234 | bool | |
1235 | help | |
1236 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap | |
1237 | Allows arch to define/use @no_unaligned_warning to possibly warn | |
1238 | about unaligned access emulation going on under the hood. | |
1239 | ||
1240 | config SYSCTL_ARCH_UNALIGN_ALLOW | |
1241 | bool | |
1242 | help | |
1243 | Enable support for /proc/sys/kernel/unaligned-trap | |
1244 | Allows arches to define/use @unaligned_enabled to runtime toggle | |
1245 | the unaligned access emulation. | |
1246 | see arch/parisc/kernel/unaligned.c for reference | |
1247 | ||
1248 | config HOTPLUG | |
1249 | def_bool y | |
1250 | ||
1251 | config HAVE_PCSPKR_PLATFORM | |
1252 | bool | |
1253 | ||
6a108a14 DR |
1254 | menuconfig EXPERT |
1255 | bool "Configure standard kernel features (expert users)" | |
f505c553 JT |
1256 | # Unhide debug options, to make the on-by-default options visible |
1257 | select DEBUG_KERNEL | |
1da177e4 LT |
1258 | help |
1259 | This option allows certain base kernel options and settings | |
1260 | to be disabled or tweaked. This is for specialized | |
1261 | environments which can tolerate a "non-standard" kernel. | |
1262 | Only use this if you really know what you are doing. | |
1263 | ||
ae81f9e3 | 1264 | config UID16 |
6a108a14 | 1265 | bool "Enable 16-bit UID system calls" if EXPERT |
af1839eb | 1266 | depends on HAVE_UID16 |
ae81f9e3 CE |
1267 | default y |
1268 | help | |
1269 | This enables the legacy 16-bit UID syscall wrappers. | |
1270 | ||
b89a8171 | 1271 | config SYSCTL_SYSCALL |
6a108a14 | 1272 | bool "Sysctl syscall support" if EXPERT |
26a7034b | 1273 | depends on PROC_SYSCTL |
c736de60 | 1274 | default n |
b89a8171 | 1275 | select SYSCTL |
ae81f9e3 | 1276 | ---help--- |
13bb7e37 EB |
1277 | sys_sysctl uses binary paths that have been found challenging |
1278 | to properly maintain and use. The interface in /proc/sys | |
1279 | using paths with ascii names is now the primary path to this | |
1280 | information. | |
b89a8171 | 1281 | |
13bb7e37 EB |
1282 | Almost nothing using the binary sysctl interface so if you are |
1283 | trying to save some space it is probably safe to disable this, | |
1284 | making your kernel marginally smaller. | |
b89a8171 | 1285 | |
c736de60 | 1286 | If unsure say N here. |
ae81f9e3 | 1287 | |
1da177e4 | 1288 | config KALLSYMS |
6a108a14 | 1289 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
1da177e4 LT |
1290 | default y |
1291 | help | |
1292 | Say Y here to let the kernel print out symbolic crash information and | |
1293 | symbolic stack backtraces. This increases the size of the kernel | |
1294 | somewhat, as all symbols have to be loaded into the kernel image. | |
1295 | ||
1296 | config KALLSYMS_ALL | |
1297 | bool "Include all symbols in kallsyms" | |
1298 | depends on DEBUG_KERNEL && KALLSYMS | |
1299 | help | |
71a83ec7 AB |
1300 | Normally kallsyms only contains the symbols of functions for nicer |
1301 | OOPS messages and backtraces (i.e., symbols from the text and inittext | |
1302 | sections). This is sufficient for most cases. And only in very rare | |
1303 | cases (e.g., when a debugger is used) all symbols are required (e.g., | |
1304 | names of variables from the data sections, etc). | |
1305 | ||
1306 | This option makes sure that all symbols are loaded into the kernel | |
1307 | image (i.e., symbols from all sections) in cost of increased kernel | |
1308 | size (depending on the kernel configuration, it may be 300KiB or | |
1309 | something like this). | |
1310 | ||
1311 | Say N unless you really need all symbols. | |
d59745ce MM |
1312 | |
1313 | config PRINTK | |
1314 | default y | |
6a108a14 | 1315 | bool "Enable support for printk" if EXPERT |
74876a98 | 1316 | select IRQ_WORK |
d59745ce MM |
1317 | help |
1318 | This option enables normal printk support. Removing it | |
1319 | eliminates most of the message strings from the kernel image | |
1320 | and makes the kernel more or less silent. As this makes it | |
1321 | very difficult to diagnose system problems, saying N here is | |
1322 | strongly discouraged. | |
1323 | ||
c8538a7a | 1324 | config BUG |
6a108a14 | 1325 | bool "BUG() support" if EXPERT |
c8538a7a MM |
1326 | default y |
1327 | help | |
1328 | Disabling this option eliminates support for BUG and WARN, reducing | |
1329 | the size of your kernel image and potentially quietly ignoring | |
1330 | numerous fatal conditions. You should only consider disabling this | |
1331 | option for embedded systems with no facilities for reporting errors. | |
1332 | Just say Y. | |
1333 | ||
708e9a79 | 1334 | config ELF_CORE |
046d662f | 1335 | depends on COREDUMP |
708e9a79 | 1336 | default y |
6a108a14 | 1337 | bool "Enable ELF core dumps" if EXPERT |
708e9a79 MM |
1338 | help |
1339 | Enable support for generating core dumps. Disabling saves about 4k. | |
1340 | ||
8761f1ab | 1341 | |
e5e1d3cb | 1342 | config PCSPKR_PLATFORM |
6a108a14 | 1343 | bool "Enable PC-Speaker support" if EXPERT |
8761f1ab | 1344 | depends on HAVE_PCSPKR_PLATFORM |
15f304b6 | 1345 | select I8253_LOCK |
e5e1d3cb SS |
1346 | default y |
1347 | help | |
1348 | This option allows to disable the internal PC-Speaker | |
1349 | support, saving some memory. | |
1350 | ||
1da177e4 LT |
1351 | config BASE_FULL |
1352 | default y | |
6a108a14 | 1353 | bool "Enable full-sized data structures for core" if EXPERT |
1da177e4 LT |
1354 | help |
1355 | Disabling this option reduces the size of miscellaneous core | |
1356 | kernel data structures. This saves memory on small machines, | |
1357 | but may reduce performance. | |
1358 | ||
1359 | config FUTEX | |
6a108a14 | 1360 | bool "Enable futex support" if EXPERT |
1da177e4 | 1361 | default y |
23f78d4a | 1362 | select RT_MUTEXES |
1da177e4 LT |
1363 | help |
1364 | Disabling this option will cause the kernel to be built without | |
1365 | support for "fast userspace mutexes". The resulting kernel may not | |
1366 | run glibc-based applications correctly. | |
1367 | ||
1368 | config EPOLL | |
6a108a14 | 1369 | bool "Enable eventpoll support" if EXPERT |
1da177e4 | 1370 | default y |
448e3cee | 1371 | select ANON_INODES |
1da177e4 LT |
1372 | help |
1373 | Disabling this option will cause the kernel to be built without | |
1374 | support for epoll family of system calls. | |
1375 | ||
fba2afaa | 1376 | config SIGNALFD |
6a108a14 | 1377 | bool "Enable signalfd() system call" if EXPERT |
448e3cee | 1378 | select ANON_INODES |
fba2afaa DL |
1379 | default y |
1380 | help | |
1381 | Enable the signalfd() system call that allows to receive signals | |
1382 | on a file descriptor. | |
1383 | ||
1384 | If unsure, say Y. | |
1385 | ||
b215e283 | 1386 | config TIMERFD |
6a108a14 | 1387 | bool "Enable timerfd() system call" if EXPERT |
448e3cee | 1388 | select ANON_INODES |
b215e283 DL |
1389 | default y |
1390 | help | |
1391 | Enable the timerfd() system call that allows to receive timer | |
1392 | events on a file descriptor. | |
1393 | ||
1394 | If unsure, say Y. | |
1395 | ||
e1ad7468 | 1396 | config EVENTFD |
6a108a14 | 1397 | bool "Enable eventfd() system call" if EXPERT |
448e3cee | 1398 | select ANON_INODES |
e1ad7468 DL |
1399 | default y |
1400 | help | |
1401 | Enable the eventfd() system call that allows to receive both | |
1402 | kernel notification (ie. KAIO) or userspace notifications. | |
1403 | ||
1404 | If unsure, say Y. | |
1405 | ||
1da177e4 | 1406 | config SHMEM |
6a108a14 | 1407 | bool "Use full shmem filesystem" if EXPERT |
1da177e4 LT |
1408 | default y |
1409 | depends on MMU | |
1410 | help | |
1411 | The shmem is an internal filesystem used to manage shared memory. | |
1412 | It is backed by swap and manages resource limits. It is also exported | |
1413 | to userspace as tmpfs if TMPFS is enabled. Disabling this | |
1414 | option replaces shmem and tmpfs with the much simpler ramfs code, | |
1415 | which may be appropriate on small systems without swap. | |
1416 | ||
ebf3f09c | 1417 | config AIO |
6a108a14 | 1418 | bool "Enable AIO support" if EXPERT |
ebf3f09c TP |
1419 | default y |
1420 | help | |
1421 | This option enables POSIX asynchronous I/O which may by used | |
657a5209 MF |
1422 | by some high performance threaded applications. Disabling |
1423 | this option saves about 7k. | |
1424 | ||
1425 | config PCI_QUIRKS | |
1426 | default y | |
1427 | bool "Enable PCI quirk workarounds" if EXPERT | |
1428 | depends on PCI | |
1429 | help | |
1430 | This enables workarounds for various PCI chipset | |
1431 | bugs/quirks. Disable this only if your target machine is | |
1432 | unaffected by PCI quirks. | |
ebf3f09c | 1433 | |
6befe5f6 RD |
1434 | config EMBEDDED |
1435 | bool "Embedded system" | |
1436 | select EXPERT | |
1437 | help | |
1438 | This option should be enabled if compiling the kernel for | |
1439 | an embedded system so certain expert options are available | |
1440 | for configuration. | |
1441 | ||
cdd6c482 | 1442 | config HAVE_PERF_EVENTS |
0793a61d | 1443 | bool |
018df72d MF |
1444 | help |
1445 | See tools/perf/design.txt for details. | |
0793a61d | 1446 | |
906010b2 PZ |
1447 | config PERF_USE_VMALLOC |
1448 | bool | |
1449 | help | |
1450 | See tools/perf/design.txt for details | |
1451 | ||
57c0c15b | 1452 | menu "Kernel Performance Events And Counters" |
0793a61d | 1453 | |
cdd6c482 | 1454 | config PERF_EVENTS |
57c0c15b | 1455 | bool "Kernel performance events and counters" |
392d65a9 | 1456 | default y if PROFILING |
cdd6c482 | 1457 | depends on HAVE_PERF_EVENTS |
4c59e467 | 1458 | select ANON_INODES |
e360adbe | 1459 | select IRQ_WORK |
0793a61d | 1460 | help |
57c0c15b IM |
1461 | Enable kernel support for various performance events provided |
1462 | by software and hardware. | |
0793a61d | 1463 | |
dd77038d | 1464 | Software events are supported either built-in or via the |
57c0c15b | 1465 | use of generic tracepoints. |
0793a61d | 1466 | |
57c0c15b IM |
1467 | Most modern CPUs support performance events via performance |
1468 | counter registers. These registers count the number of certain | |
0793a61d TG |
1469 | types of hw events: such as instructions executed, cachemisses |
1470 | suffered, or branches mis-predicted - without slowing down the | |
1471 | kernel or applications. These registers can also trigger interrupts | |
1472 | when a threshold number of events have passed - and can thus be | |
1473 | used to profile the code that runs on that CPU. | |
1474 | ||
57c0c15b | 1475 | The Linux Performance Event subsystem provides an abstraction of |
dd77038d | 1476 | these software and hardware event capabilities, available via a |
57c0c15b | 1477 | system call and used by the "perf" utility in tools/perf/. It |
0793a61d TG |
1478 | provides per task and per CPU counters, and it provides event |
1479 | capabilities on top of those. | |
1480 | ||
1481 | Say Y if unsure. | |
1482 | ||
906010b2 PZ |
1483 | config DEBUG_PERF_USE_VMALLOC |
1484 | default n | |
1485 | bool "Debug: use vmalloc to back perf mmap() buffers" | |
1486 | depends on PERF_EVENTS && DEBUG_KERNEL | |
1487 | select PERF_USE_VMALLOC | |
1488 | help | |
1489 | Use vmalloc memory to back perf mmap() buffers. | |
1490 | ||
1491 | Mostly useful for debugging the vmalloc code on platforms | |
1492 | that don't require it. | |
1493 | ||
1494 | Say N if unsure. | |
1495 | ||
0793a61d TG |
1496 | endmenu |
1497 | ||
f8891e5e CL |
1498 | config VM_EVENT_COUNTERS |
1499 | default y | |
6a108a14 | 1500 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
f8891e5e | 1501 | help |
2aea4fb6 PJ |
1502 | VM event counters are needed for event counts to be shown. |
1503 | This option allows the disabling of the VM event counters | |
6a108a14 | 1504 | on EXPERT systems. /proc/vmstat will only show page counts |
2aea4fb6 | 1505 | if VM event counters are disabled. |
f8891e5e | 1506 | |
41ecc55b CL |
1507 | config SLUB_DEBUG |
1508 | default y | |
6a108a14 | 1509 | bool "Enable SLUB debugging support" if EXPERT |
f6acb635 | 1510 | depends on SLUB && SYSFS |
41ecc55b CL |
1511 | help |
1512 | SLUB has extensive debug support features. Disabling these can | |
1513 | result in significant savings in code size. This also disables | |
1514 | SLUB sysfs support. /sys/slab will not exist and there will be | |
1515 | no support for cache validation etc. | |
1516 | ||
b943c460 RD |
1517 | config COMPAT_BRK |
1518 | bool "Disable heap randomization" | |
1519 | default y | |
1520 | help | |
1521 | Randomizing heap placement makes heap exploits harder, but it | |
1522 | also breaks ancient binaries (including anything libc5 based). | |
1523 | This option changes the bootup default to heap randomization | |
692105b8 | 1524 | disabled, and can be overridden at runtime by setting |
b943c460 RD |
1525 | /proc/sys/kernel/randomize_va_space to 2. |
1526 | ||
1527 | On non-ancient distros (post-2000 ones) N is usually a safe choice. | |
1528 | ||
81819f0f CL |
1529 | choice |
1530 | prompt "Choose SLAB allocator" | |
a0acd820 | 1531 | default SLUB |
81819f0f CL |
1532 | help |
1533 | This option allows to select a slab allocator. | |
1534 | ||
1535 | config SLAB | |
1536 | bool "SLAB" | |
1537 | help | |
1538 | The regular slab allocator that is established and known to work | |
34013886 | 1539 | well in all environments. It organizes cache hot objects in |
02f56210 | 1540 | per cpu and per node queues. |
81819f0f CL |
1541 | |
1542 | config SLUB | |
81819f0f CL |
1543 | bool "SLUB (Unqueued Allocator)" |
1544 | help | |
1545 | SLUB is a slab allocator that minimizes cache line usage | |
1546 | instead of managing queues of cached objects (SLAB approach). | |
1547 | Per cpu caching is realized using slabs of objects instead | |
1548 | of queues of objects. SLUB can use memory efficiently | |
02f56210 SA |
1549 | and has enhanced diagnostics. SLUB is the default choice for |
1550 | a slab allocator. | |
81819f0f CL |
1551 | |
1552 | config SLOB | |
6a108a14 | 1553 | depends on EXPERT |
81819f0f CL |
1554 | bool "SLOB (Simple Allocator)" |
1555 | help | |
37291458 MM |
1556 | SLOB replaces the stock allocator with a drastically simpler |
1557 | allocator. SLOB is generally more space efficient but | |
1558 | does not perform as well on large systems. | |
81819f0f CL |
1559 | |
1560 | endchoice | |
1561 | ||
ea637639 JZ |
1562 | config MMAP_ALLOW_UNINITIALIZED |
1563 | bool "Allow mmapped anonymous memory to be uninitialized" | |
6a108a14 | 1564 | depends on EXPERT && !MMU |
ea637639 JZ |
1565 | default n |
1566 | help | |
1567 | Normally, and according to the Linux spec, anonymous memory obtained | |
1568 | from mmap() has it's contents cleared before it is passed to | |
1569 | userspace. Enabling this config option allows you to request that | |
1570 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus | |
1571 | providing a huge performance boost. If this option is not enabled, | |
1572 | then the flag will be ignored. | |
1573 | ||
1574 | This is taken advantage of by uClibc's malloc(), and also by | |
1575 | ELF-FDPIC binfmt's brk and stack allocator. | |
1576 | ||
1577 | Because of the obvious security issues, this option should only be | |
1578 | enabled on embedded devices where you control what is run in | |
1579 | userspace. Since that isn't generally a problem on no-MMU systems, | |
1580 | it is normally safe to say Y here. | |
1581 | ||
1582 | See Documentation/nommu-mmap.txt for more information. | |
1583 | ||
125e5645 | 1584 | config PROFILING |
b309a294 | 1585 | bool "Profiling support" |
125e5645 MD |
1586 | help |
1587 | Say Y here to enable the extended profiling support mechanisms used | |
1588 | by profilers such as OProfile. | |
1589 | ||
5f87f112 IM |
1590 | # |
1591 | # Place an empty function call at each tracepoint site. Can be | |
1592 | # dynamically changed for a probe function. | |
1593 | # | |
97e1c18e | 1594 | config TRACEPOINTS |
5f87f112 | 1595 | bool |
97e1c18e | 1596 | |
fb32e03f MD |
1597 | source "arch/Kconfig" |
1598 | ||
1da177e4 LT |
1599 | endmenu # General setup |
1600 | ||
ee7e5516 DB |
1601 | config HAVE_GENERIC_DMA_COHERENT |
1602 | bool | |
1603 | default n | |
1604 | ||
158a9624 LT |
1605 | config SLABINFO |
1606 | bool | |
1607 | depends on PROC_FS | |
0f389ec6 | 1608 | depends on SLAB || SLUB_DEBUG |
158a9624 LT |
1609 | default y |
1610 | ||
ae81f9e3 CE |
1611 | config RT_MUTEXES |
1612 | boolean | |
ae81f9e3 | 1613 | |
1da177e4 LT |
1614 | config BASE_SMALL |
1615 | int | |
1616 | default 0 if BASE_FULL | |
1617 | default 1 if !BASE_FULL | |
1618 | ||
66da5733 | 1619 | menuconfig MODULES |
1da177e4 LT |
1620 | bool "Enable loadable module support" |
1621 | help | |
1622 | Kernel modules are small pieces of compiled code which can | |
1623 | be inserted in the running kernel, rather than being | |
1624 | permanently built into the kernel. You use the "modprobe" | |
1625 | tool to add (and sometimes remove) them. If you say Y here, | |
1626 | many parts of the kernel can be built as modules (by | |
1627 | answering M instead of Y where indicated): this is most | |
1628 | useful for infrequently used options which are not required | |
1629 | for booting. For more information, see the man pages for | |
1630 | modprobe, lsmod, modinfo, insmod and rmmod. | |
1631 | ||
1632 | If you say Y here, you will need to run "make | |
1633 | modules_install" to put the modules under /lib/modules/ | |
1634 | where modprobe can find them (you may need to be root to do | |
1635 | this). | |
1636 | ||
1637 | If unsure, say Y. | |
1638 | ||
0b0de144 RD |
1639 | if MODULES |
1640 | ||
826e4506 LT |
1641 | config MODULE_FORCE_LOAD |
1642 | bool "Forced module loading" | |
826e4506 LT |
1643 | default n |
1644 | help | |
91e37a79 RR |
1645 | Allow loading of modules without version information (ie. modprobe |
1646 | --force). Forced module loading sets the 'F' (forced) taint flag and | |
1647 | is usually a really bad idea. | |
826e4506 | 1648 | |
1da177e4 LT |
1649 | config MODULE_UNLOAD |
1650 | bool "Module unloading" | |
1da177e4 LT |
1651 | help |
1652 | Without this option you will not be able to unload any | |
1653 | modules (note that some modules may not be unloadable | |
f7f5b675 DV |
1654 | anyway), which makes your kernel smaller, faster |
1655 | and simpler. If unsure, say Y. | |
1da177e4 LT |
1656 | |
1657 | config MODULE_FORCE_UNLOAD | |
1658 | bool "Forced module unloading" | |
19c92399 | 1659 | depends on MODULE_UNLOAD |
1da177e4 LT |
1660 | help |
1661 | This option allows you to force a module to unload, even if the | |
1662 | kernel believes it is unsafe: the kernel will remove the module | |
1663 | without waiting for anyone to stop using it (using the -f option to | |
1664 | rmmod). This is mainly for kernel developers and desperate users. | |
1665 | If unsure, say N. | |
1666 | ||
1da177e4 | 1667 | config MODVERSIONS |
0d541643 | 1668 | bool "Module versioning support" |
1da177e4 LT |
1669 | help |
1670 | Usually, you have to use modules compiled with your kernel. | |
1671 | Saying Y here makes it sometimes possible to use modules | |
1672 | compiled for different kernels, by adding enough information | |
1673 | to the modules to (hopefully) spot any changes which would | |
1674 | make them incompatible with the kernel you are running. If | |
1675 | unsure, say N. | |
1676 | ||
1677 | config MODULE_SRCVERSION_ALL | |
1678 | bool "Source checksum for all modules" | |
1da177e4 LT |
1679 | help |
1680 | Modules which contain a MODULE_VERSION get an extra "srcversion" | |
1681 | field inserted into their modinfo section, which contains a | |
1682 | sum of the source files which made it. This helps maintainers | |
1683 | see exactly which source was used to build a module (since | |
1684 | others sometimes change the module source without updating | |
1685 | the version). With this option, such a "srcversion" field | |
1686 | will be created for all modules. If unsure, say N. | |
1687 | ||
106a4ee2 RR |
1688 | config MODULE_SIG |
1689 | bool "Module signature verification" | |
1690 | depends on MODULES | |
48ba2462 DH |
1691 | select KEYS |
1692 | select CRYPTO | |
1693 | select ASYMMETRIC_KEY_TYPE | |
1694 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE | |
1695 | select PUBLIC_KEY_ALGO_RSA | |
1696 | select ASN1 | |
1697 | select OID_REGISTRY | |
1698 | select X509_CERTIFICATE_PARSER | |
106a4ee2 RR |
1699 | help |
1700 | Check modules for valid signatures upon load: the signature | |
1701 | is simply appended to the module. For more information see | |
1702 | Documentation/module-signing.txt. | |
1703 | ||
ea0b6dcf DH |
1704 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
1705 | module DOES NOT get stripped after being signed. This includes the | |
1706 | debuginfo strip done by some packagers (such as rpmbuild) and | |
1707 | inclusion into an initramfs that wants the module size reduced. | |
1708 | ||
106a4ee2 RR |
1709 | config MODULE_SIG_FORCE |
1710 | bool "Require modules to be validly signed" | |
1711 | depends on MODULE_SIG | |
1712 | help | |
1713 | Reject unsigned modules or signed modules for which we don't have a | |
1714 | key. Without this, such modules will simply taint the kernel. | |
ea0b6dcf | 1715 | |
d9d8d7ed MM |
1716 | config MODULE_SIG_ALL |
1717 | bool "Automatically sign all modules" | |
1718 | default y | |
1719 | depends on MODULE_SIG | |
1720 | help | |
1721 | Sign all modules during make modules_install. Without this option, | |
1722 | modules must be signed manually, using the scripts/sign-file tool. | |
1723 | ||
1724 | comment "Do not forget to sign required modules with scripts/sign-file" | |
1725 | depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL | |
1726 | ||
ea0b6dcf DH |
1727 | choice |
1728 | prompt "Which hash algorithm should modules be signed with?" | |
1729 | depends on MODULE_SIG | |
1730 | help | |
1731 | This determines which sort of hashing algorithm will be used during | |
1732 | signature generation. This algorithm _must_ be built into the kernel | |
1733 | directly so that signature verification can take place. It is not | |
1734 | possible to load a signed module containing the algorithm to check | |
1735 | the signature on that module. | |
1736 | ||
1737 | config MODULE_SIG_SHA1 | |
1738 | bool "Sign modules with SHA-1" | |
1739 | select CRYPTO_SHA1 | |
1740 | ||
1741 | config MODULE_SIG_SHA224 | |
1742 | bool "Sign modules with SHA-224" | |
1743 | select CRYPTO_SHA256 | |
1744 | ||
1745 | config MODULE_SIG_SHA256 | |
1746 | bool "Sign modules with SHA-256" | |
1747 | select CRYPTO_SHA256 | |
1748 | ||
1749 | config MODULE_SIG_SHA384 | |
1750 | bool "Sign modules with SHA-384" | |
1751 | select CRYPTO_SHA512 | |
1752 | ||
1753 | config MODULE_SIG_SHA512 | |
1754 | bool "Sign modules with SHA-512" | |
1755 | select CRYPTO_SHA512 | |
1756 | ||
1757 | endchoice | |
1758 | ||
22753674 MM |
1759 | config MODULE_SIG_HASH |
1760 | string | |
1761 | depends on MODULE_SIG | |
1762 | default "sha1" if MODULE_SIG_SHA1 | |
1763 | default "sha224" if MODULE_SIG_SHA224 | |
1764 | default "sha256" if MODULE_SIG_SHA256 | |
1765 | default "sha384" if MODULE_SIG_SHA384 | |
1766 | default "sha512" if MODULE_SIG_SHA512 | |
1767 | ||
0b0de144 RD |
1768 | endif # MODULES |
1769 | ||
98a79d6a RR |
1770 | config INIT_ALL_POSSIBLE |
1771 | bool | |
1772 | help | |
5f054e31 RR |
1773 | Back when each arch used to define their own cpu_online_mask and |
1774 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask | |
98a79d6a RR |
1775 | with all 1s, and others with all 0s. When they were centralised, |
1776 | it was better to provide this option than to break all the archs | |
692105b8 | 1777 | and have several arch maintainers pursuing me down dark alleys. |
98a79d6a | 1778 | |
1da177e4 LT |
1779 | config STOP_MACHINE |
1780 | bool | |
1781 | default y | |
1782 | depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU | |
1783 | help | |
1784 | Need stop_machine() primitive. | |
3a65dfe8 | 1785 | |
3a65dfe8 | 1786 | source "block/Kconfig" |
e98c3202 AK |
1787 | |
1788 | config PREEMPT_NOTIFIERS | |
1789 | bool | |
e260be67 | 1790 | |
16295bec SK |
1791 | config PADATA |
1792 | depends on SMP | |
1793 | bool | |
1794 | ||
754b7b63 AK |
1795 | # Can be selected by architectures with broken toolchains |
1796 | # that get confused by correct const<->read_only section | |
1797 | # mappings | |
1798 | config BROKEN_RODATA | |
1799 | bool | |
1800 | ||
4520c6a4 DH |
1801 | config ASN1 |
1802 | tristate | |
1803 | help | |
1804 | Build a simple ASN.1 grammar compiler that produces a bytecode output | |
1805 | that can be interpreted by the ASN.1 stream decoder and used to | |
1806 | inform it as to what tags are to be expected in a stream and what | |
1807 | functions to call on what tags. | |
1808 | ||
6beb0009 | 1809 | source "kernel/Kconfig.locks" |