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1 | config ARCH | |
2 | string | |
3 | option env="ARCH" | |
4 | ||
5 | config KERNELVERSION | |
6 | string | |
7 | option env="KERNELVERSION" | |
8 | ||
9 | config DEFCONFIG_LIST | |
10 | string | |
11 | depends on !UML | |
12 | option defconfig_list | |
13 | default "/lib/modules/$UNAME_RELEASE/.config" | |
14 | default "/etc/kernel-config" | |
15 | default "/boot/config-$UNAME_RELEASE" | |
16 | default "$ARCH_DEFCONFIG" | |
17 | default "arch/$ARCH/defconfig" | |
18 | ||
19 | menu "General setup" | |
20 | ||
21 | config EXPERIMENTAL | |
22 | bool "Prompt for development and/or incomplete code/drivers" | |
23 | ---help--- | |
24 | Some of the various things that Linux supports (such as network | |
25 | drivers, file systems, network protocols, etc.) can be in a state | |
26 | of development where the functionality, stability, or the level of | |
27 | testing is not yet high enough for general use. This is usually | |
28 | known as the "alpha-test" phase among developers. If a feature is | |
29 | currently in alpha-test, then the developers usually discourage | |
30 | uninformed widespread use of this feature by the general public to | |
31 | avoid "Why doesn't this work?" type mail messages. However, active | |
32 | testing and use of these systems is welcomed. Just be aware that it | |
33 | may not meet the normal level of reliability or it may fail to work | |
34 | in some special cases. Detailed bug reports from people familiar | |
35 | with the kernel internals are usually welcomed by the developers | |
36 | (before submitting bug reports, please read the documents | |
37 | <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, | |
38 | <file:Documentation/BUG-HUNTING>, and | |
39 | <file:Documentation/oops-tracing.txt> in the kernel source). | |
40 | ||
41 | This option will also make obsoleted drivers available. These are | |
42 | drivers that have been replaced by something else, and/or are | |
43 | scheduled to be removed in a future kernel release. | |
44 | ||
45 | Unless you intend to help test and develop a feature or driver that | |
46 | falls into this category, or you have a situation that requires | |
47 | using these features, you should probably say N here, which will | |
48 | cause the configurator to present you with fewer choices. If | |
49 | you say Y here, you will be offered the choice of using features or | |
50 | drivers that are currently considered to be in the alpha-test phase. | |
51 | ||
52 | config BROKEN | |
53 | bool | |
54 | ||
55 | config BROKEN_ON_SMP | |
56 | bool | |
57 | depends on BROKEN || !SMP | |
58 | default y | |
59 | ||
60 | config LOCK_KERNEL | |
61 | bool | |
62 | depends on SMP || PREEMPT | |
63 | default y | |
64 | ||
65 | config INIT_ENV_ARG_LIMIT | |
66 | int | |
67 | default 32 if !UML | |
68 | default 128 if UML | |
69 | help | |
70 | Maximum of each of the number of arguments and environment | |
71 | variables passed to init from the kernel command line. | |
72 | ||
73 | ||
74 | config LOCALVERSION | |
75 | string "Local version - append to kernel release" | |
76 | help | |
77 | Append an extra string to the end of your kernel version. | |
78 | This will show up when you type uname, for example. | |
79 | The string you set here will be appended after the contents of | |
80 | any files with a filename matching localversion* in your | |
81 | object and source tree, in that order. Your total string can | |
82 | be a maximum of 64 characters. | |
83 | ||
84 | config LOCALVERSION_AUTO | |
85 | bool "Automatically append version information to the version string" | |
86 | default y | |
87 | help | |
88 | This will try to automatically determine if the current tree is a | |
89 | release tree by looking for git tags that belong to the current | |
90 | top of tree revision. | |
91 | ||
92 | A string of the format -gxxxxxxxx will be added to the localversion | |
93 | if a git-based tree is found. The string generated by this will be | |
94 | appended after any matching localversion* files, and after the value | |
95 | set in CONFIG_LOCALVERSION. | |
96 | ||
97 | (The actual string used here is the first eight characters produced | |
98 | by running the command: | |
99 | ||
100 | $ git rev-parse --verify HEAD | |
101 | ||
102 | which is done within the script "scripts/setlocalversion".) | |
103 | ||
104 | config HAVE_KERNEL_GZIP | |
105 | bool | |
106 | ||
107 | config HAVE_KERNEL_BZIP2 | |
108 | bool | |
109 | ||
110 | config HAVE_KERNEL_LZMA | |
111 | bool | |
112 | ||
113 | choice | |
114 | prompt "Kernel compression mode" | |
115 | default KERNEL_GZIP | |
116 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA | |
117 | help | |
118 | The linux kernel is a kind of self-extracting executable. | |
119 | Several compression algorithms are available, which differ | |
120 | in efficiency, compression and decompression speed. | |
121 | Compression speed is only relevant when building a kernel. | |
122 | Decompression speed is relevant at each boot. | |
123 | ||
124 | If you have any problems with bzip2 or lzma compressed | |
125 | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older | |
126 | version of this functionality (bzip2 only), for 2.4, was | |
127 | supplied by Christian Ludwig) | |
128 | ||
129 | High compression options are mostly useful for users, who | |
130 | are low on disk space (embedded systems), but for whom ram | |
131 | size matters less. | |
132 | ||
133 | If in doubt, select 'gzip' | |
134 | ||
135 | config KERNEL_GZIP | |
136 | bool "Gzip" | |
137 | depends on HAVE_KERNEL_GZIP | |
138 | help | |
139 | The old and tried gzip compression. Its compression ratio is | |
140 | the poorest among the 3 choices; however its speed (both | |
141 | compression and decompression) is the fastest. | |
142 | ||
143 | config KERNEL_BZIP2 | |
144 | bool "Bzip2" | |
145 | depends on HAVE_KERNEL_BZIP2 | |
146 | help | |
147 | Its compression ratio and speed is intermediate. | |
148 | Decompression speed is slowest among the three. The kernel | |
149 | size is about 10% smaller with bzip2, in comparison to gzip. | |
150 | Bzip2 uses a large amount of memory. For modern kernels you | |
151 | will need at least 8MB RAM or more for booting. | |
152 | ||
153 | config KERNEL_LZMA | |
154 | bool "LZMA" | |
155 | depends on HAVE_KERNEL_LZMA | |
156 | help | |
157 | The most recent compression algorithm. | |
158 | Its ratio is best, decompression speed is between the other | |
159 | two. Compression is slowest. The kernel size is about 33% | |
160 | smaller with LZMA in comparison to gzip. | |
161 | ||
162 | endchoice | |
163 | ||
164 | config SWAP | |
165 | bool "Support for paging of anonymous memory (swap)" | |
166 | depends on MMU && BLOCK | |
167 | default y | |
168 | help | |
169 | This option allows you to choose whether you want to have support | |
170 | for so called swap devices or swap files in your kernel that are | |
171 | used to provide more virtual memory than the actual RAM present | |
172 | in your computer. If unsure say Y. | |
173 | ||
174 | config SYSVIPC | |
175 | bool "System V IPC" | |
176 | ---help--- | |
177 | Inter Process Communication is a suite of library functions and | |
178 | system calls which let processes (running programs) synchronize and | |
179 | exchange information. It is generally considered to be a good thing, | |
180 | and some programs won't run unless you say Y here. In particular, if | |
181 | you want to run the DOS emulator dosemu under Linux (read the | |
182 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), | |
183 | you'll need to say Y here. | |
184 | ||
185 | You can find documentation about IPC with "info ipc" and also in | |
186 | section 6.4 of the Linux Programmer's Guide, available from | |
187 | <http://www.tldp.org/guides.html>. | |
188 | ||
189 | config SYSVIPC_SYSCTL | |
190 | bool | |
191 | depends on SYSVIPC | |
192 | depends on SYSCTL | |
193 | default y | |
194 | ||
195 | config POSIX_MQUEUE | |
196 | bool "POSIX Message Queues" | |
197 | depends on NET && EXPERIMENTAL | |
198 | ---help--- | |
199 | POSIX variant of message queues is a part of IPC. In POSIX message | |
200 | queues every message has a priority which decides about succession | |
201 | of receiving it by a process. If you want to compile and run | |
202 | programs written e.g. for Solaris with use of its POSIX message | |
203 | queues (functions mq_*) say Y here. | |
204 | ||
205 | POSIX message queues are visible as a filesystem called 'mqueue' | |
206 | and can be mounted somewhere if you want to do filesystem | |
207 | operations on message queues. | |
208 | ||
209 | If unsure, say Y. | |
210 | ||
211 | config POSIX_MQUEUE_SYSCTL | |
212 | bool | |
213 | depends on POSIX_MQUEUE | |
214 | depends on SYSCTL | |
215 | default y | |
216 | ||
217 | config BSD_PROCESS_ACCT | |
218 | bool "BSD Process Accounting" | |
219 | help | |
220 | If you say Y here, a user level program will be able to instruct the | |
221 | kernel (via a special system call) to write process accounting | |
222 | information to a file: whenever a process exits, information about | |
223 | that process will be appended to the file by the kernel. The | |
224 | information includes things such as creation time, owning user, | |
225 | command name, memory usage, controlling terminal etc. (the complete | |
226 | list is in the struct acct in <file:include/linux/acct.h>). It is | |
227 | up to the user level program to do useful things with this | |
228 | information. This is generally a good idea, so say Y. | |
229 | ||
230 | config BSD_PROCESS_ACCT_V3 | |
231 | bool "BSD Process Accounting version 3 file format" | |
232 | depends on BSD_PROCESS_ACCT | |
233 | default n | |
234 | help | |
235 | If you say Y here, the process accounting information is written | |
236 | in a new file format that also logs the process IDs of each | |
237 | process and it's parent. Note that this file format is incompatible | |
238 | with previous v0/v1/v2 file formats, so you will need updated tools | |
239 | for processing it. A preliminary version of these tools is available | |
240 | at <http://www.gnu.org/software/acct/>. | |
241 | ||
242 | config TASKSTATS | |
243 | bool "Export task/process statistics through netlink (EXPERIMENTAL)" | |
244 | depends on NET | |
245 | default n | |
246 | help | |
247 | Export selected statistics for tasks/processes through the | |
248 | generic netlink interface. Unlike BSD process accounting, the | |
249 | statistics are available during the lifetime of tasks/processes as | |
250 | responses to commands. Like BSD accounting, they are sent to user | |
251 | space on task exit. | |
252 | ||
253 | Say N if unsure. | |
254 | ||
255 | config TASK_DELAY_ACCT | |
256 | bool "Enable per-task delay accounting (EXPERIMENTAL)" | |
257 | depends on TASKSTATS | |
258 | help | |
259 | Collect information on time spent by a task waiting for system | |
260 | resources like cpu, synchronous block I/O completion and swapping | |
261 | in pages. Such statistics can help in setting a task's priorities | |
262 | relative to other tasks for cpu, io, rss limits etc. | |
263 | ||
264 | Say N if unsure. | |
265 | ||
266 | config TASK_XACCT | |
267 | bool "Enable extended accounting over taskstats (EXPERIMENTAL)" | |
268 | depends on TASKSTATS | |
269 | help | |
270 | Collect extended task accounting data and send the data | |
271 | to userland for processing over the taskstats interface. | |
272 | ||
273 | Say N if unsure. | |
274 | ||
275 | config TASK_IO_ACCOUNTING | |
276 | bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" | |
277 | depends on TASK_XACCT | |
278 | help | |
279 | Collect information on the number of bytes of storage I/O which this | |
280 | task has caused. | |
281 | ||
282 | Say N if unsure. | |
283 | ||
284 | config AUDIT | |
285 | bool "Auditing support" | |
286 | depends on NET | |
287 | help | |
288 | Enable auditing infrastructure that can be used with another | |
289 | kernel subsystem, such as SELinux (which requires this for | |
290 | logging of avc messages output). Does not do system-call | |
291 | auditing without CONFIG_AUDITSYSCALL. | |
292 | ||
293 | config AUDITSYSCALL | |
294 | bool "Enable system-call auditing support" | |
295 | depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH) | |
296 | default y if SECURITY_SELINUX | |
297 | help | |
298 | Enable low-overhead system-call auditing infrastructure that | |
299 | can be used independently or with another kernel subsystem, | |
300 | such as SELinux. To use audit's filesystem watch feature, please | |
301 | ensure that INOTIFY is configured. | |
302 | ||
303 | config AUDIT_TREE | |
304 | def_bool y | |
305 | depends on AUDITSYSCALL | |
306 | select INOTIFY | |
307 | ||
308 | menu "RCU Subsystem" | |
309 | ||
310 | choice | |
311 | prompt "RCU Implementation" | |
312 | default TREE_RCU | |
313 | ||
314 | config CLASSIC_RCU | |
315 | bool "Classic RCU" | |
316 | help | |
317 | This option selects the classic RCU implementation that is | |
318 | designed for best read-side performance on non-realtime | |
319 | systems. | |
320 | ||
321 | Select this option if you are unsure. | |
322 | ||
323 | config TREE_RCU | |
324 | bool "Tree-based hierarchical RCU" | |
325 | help | |
326 | This option selects the RCU implementation that is | |
327 | designed for very large SMP system with hundreds or | |
328 | thousands of CPUs. | |
329 | ||
330 | config PREEMPT_RCU | |
331 | bool "Preemptible RCU" | |
332 | depends on PREEMPT | |
333 | help | |
334 | This option reduces the latency of the kernel by making certain | |
335 | RCU sections preemptible. Normally RCU code is non-preemptible, if | |
336 | this option is selected then read-only RCU sections become | |
337 | preemptible. This helps latency, but may expose bugs due to | |
338 | now-naive assumptions about each RCU read-side critical section | |
339 | remaining on a given CPU through its execution. | |
340 | ||
341 | endchoice | |
342 | ||
343 | config RCU_TRACE | |
344 | bool "Enable tracing for RCU" | |
345 | depends on TREE_RCU || PREEMPT_RCU | |
346 | help | |
347 | This option provides tracing in RCU which presents stats | |
348 | in debugfs for debugging RCU implementation. | |
349 | ||
350 | Say Y here if you want to enable RCU tracing | |
351 | Say N if you are unsure. | |
352 | ||
353 | config RCU_FANOUT | |
354 | int "Tree-based hierarchical RCU fanout value" | |
355 | range 2 64 if 64BIT | |
356 | range 2 32 if !64BIT | |
357 | depends on TREE_RCU | |
358 | default 64 if 64BIT | |
359 | default 32 if !64BIT | |
360 | help | |
361 | This option controls the fanout of hierarchical implementations | |
362 | of RCU, allowing RCU to work efficiently on machines with | |
363 | large numbers of CPUs. This value must be at least the cube | |
364 | root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit | |
365 | systems and up to 262,144 for 64-bit systems. | |
366 | ||
367 | Select a specific number if testing RCU itself. | |
368 | Take the default if unsure. | |
369 | ||
370 | config RCU_FANOUT_EXACT | |
371 | bool "Disable tree-based hierarchical RCU auto-balancing" | |
372 | depends on TREE_RCU | |
373 | default n | |
374 | help | |
375 | This option forces use of the exact RCU_FANOUT value specified, | |
376 | regardless of imbalances in the hierarchy. This is useful for | |
377 | testing RCU itself, and might one day be useful on systems with | |
378 | strong NUMA behavior. | |
379 | ||
380 | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. | |
381 | ||
382 | Say N if unsure. | |
383 | ||
384 | config TREE_RCU_TRACE | |
385 | def_bool RCU_TRACE && TREE_RCU | |
386 | select DEBUG_FS | |
387 | help | |
388 | This option provides tracing for the TREE_RCU implementation, | |
389 | permitting Makefile to trivially select kernel/rcutree_trace.c. | |
390 | ||
391 | config PREEMPT_RCU_TRACE | |
392 | def_bool RCU_TRACE && PREEMPT_RCU | |
393 | select DEBUG_FS | |
394 | help | |
395 | This option provides tracing for the PREEMPT_RCU implementation, | |
396 | permitting Makefile to trivially select kernel/rcupreempt_trace.c. | |
397 | ||
398 | endmenu # "RCU Subsystem" | |
399 | ||
400 | config IKCONFIG | |
401 | tristate "Kernel .config support" | |
402 | ---help--- | |
403 | This option enables the complete Linux kernel ".config" file | |
404 | contents to be saved in the kernel. It provides documentation | |
405 | of which kernel options are used in a running kernel or in an | |
406 | on-disk kernel. This information can be extracted from the kernel | |
407 | image file with the script scripts/extract-ikconfig and used as | |
408 | input to rebuild the current kernel or to build another kernel. | |
409 | It can also be extracted from a running kernel by reading | |
410 | /proc/config.gz if enabled (below). | |
411 | ||
412 | config IKCONFIG_PROC | |
413 | bool "Enable access to .config through /proc/config.gz" | |
414 | depends on IKCONFIG && PROC_FS | |
415 | ---help--- | |
416 | This option enables access to the kernel configuration file | |
417 | through /proc/config.gz. | |
418 | ||
419 | config LOG_BUF_SHIFT | |
420 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | |
421 | range 12 21 | |
422 | default 17 | |
423 | help | |
424 | Select kernel log buffer size as a power of 2. | |
425 | Examples: | |
426 | 17 => 128 KB | |
427 | 16 => 64 KB | |
428 | 15 => 32 KB | |
429 | 14 => 16 KB | |
430 | 13 => 8 KB | |
431 | 12 => 4 KB | |
432 | ||
433 | # | |
434 | # Architectures with an unreliable sched_clock() should select this: | |
435 | # | |
436 | config HAVE_UNSTABLE_SCHED_CLOCK | |
437 | bool | |
438 | ||
439 | config GROUP_SCHED | |
440 | bool "Group CPU scheduler" | |
441 | depends on EXPERIMENTAL | |
442 | default n | |
443 | help | |
444 | This feature lets CPU scheduler recognize task groups and control CPU | |
445 | bandwidth allocation to such task groups. | |
446 | In order to create a group from arbitrary set of processes, use | |
447 | CONFIG_CGROUPS. (See Control Group support.) | |
448 | ||
449 | config FAIR_GROUP_SCHED | |
450 | bool "Group scheduling for SCHED_OTHER" | |
451 | depends on GROUP_SCHED | |
452 | default GROUP_SCHED | |
453 | ||
454 | config RT_GROUP_SCHED | |
455 | bool "Group scheduling for SCHED_RR/FIFO" | |
456 | depends on EXPERIMENTAL | |
457 | depends on GROUP_SCHED | |
458 | default n | |
459 | help | |
460 | This feature lets you explicitly allocate real CPU bandwidth | |
461 | to users or control groups (depending on the "Basis for grouping tasks" | |
462 | setting below. If enabled, it will also make it impossible to | |
463 | schedule realtime tasks for non-root users until you allocate | |
464 | realtime bandwidth for them. | |
465 | See Documentation/scheduler/sched-rt-group.txt for more information. | |
466 | ||
467 | choice | |
468 | depends on GROUP_SCHED | |
469 | prompt "Basis for grouping tasks" | |
470 | default USER_SCHED | |
471 | ||
472 | config USER_SCHED | |
473 | bool "user id" | |
474 | help | |
475 | This option will choose userid as the basis for grouping | |
476 | tasks, thus providing equal CPU bandwidth to each user. | |
477 | ||
478 | config CGROUP_SCHED | |
479 | bool "Control groups" | |
480 | depends on CGROUPS | |
481 | help | |
482 | This option allows you to create arbitrary task groups | |
483 | using the "cgroup" pseudo filesystem and control | |
484 | the cpu bandwidth allocated to each such task group. | |
485 | Refer to Documentation/cgroups/cgroups.txt for more | |
486 | information on "cgroup" pseudo filesystem. | |
487 | ||
488 | endchoice | |
489 | ||
490 | menuconfig CGROUPS | |
491 | boolean "Control Group support" | |
492 | help | |
493 | This option adds support for grouping sets of processes together, for | |
494 | use with process control subsystems such as Cpusets, CFS, memory | |
495 | controls or device isolation. | |
496 | See | |
497 | - Documentation/scheduler/sched-design-CFS.txt (CFS) | |
498 | - Documentation/cgroups/ (features for grouping, isolation | |
499 | and resource control) | |
500 | ||
501 | Say N if unsure. | |
502 | ||
503 | if CGROUPS | |
504 | ||
505 | config CGROUP_DEBUG | |
506 | bool "Example debug cgroup subsystem" | |
507 | depends on CGROUPS | |
508 | default n | |
509 | help | |
510 | This option enables a simple cgroup subsystem that | |
511 | exports useful debugging information about the cgroups | |
512 | framework. | |
513 | ||
514 | Say N if unsure. | |
515 | ||
516 | config CGROUP_NS | |
517 | bool "Namespace cgroup subsystem" | |
518 | depends on CGROUPS | |
519 | help | |
520 | Provides a simple namespace cgroup subsystem to | |
521 | provide hierarchical naming of sets of namespaces, | |
522 | for instance virtual servers and checkpoint/restart | |
523 | jobs. | |
524 | ||
525 | config CGROUP_FREEZER | |
526 | bool "Freezer cgroup subsystem" | |
527 | depends on CGROUPS | |
528 | help | |
529 | Provides a way to freeze and unfreeze all tasks in a | |
530 | cgroup. | |
531 | ||
532 | config CGROUP_DEVICE | |
533 | bool "Device controller for cgroups" | |
534 | depends on CGROUPS && EXPERIMENTAL | |
535 | help | |
536 | Provides a cgroup implementing whitelists for devices which | |
537 | a process in the cgroup can mknod or open. | |
538 | ||
539 | config CPUSETS | |
540 | bool "Cpuset support" | |
541 | depends on CGROUPS | |
542 | help | |
543 | This option will let you create and manage CPUSETs which | |
544 | allow dynamically partitioning a system into sets of CPUs and | |
545 | Memory Nodes and assigning tasks to run only within those sets. | |
546 | This is primarily useful on large SMP or NUMA systems. | |
547 | ||
548 | Say N if unsure. | |
549 | ||
550 | config PROC_PID_CPUSET | |
551 | bool "Include legacy /proc/<pid>/cpuset file" | |
552 | depends on CPUSETS | |
553 | default y | |
554 | ||
555 | config CGROUP_CPUACCT | |
556 | bool "Simple CPU accounting cgroup subsystem" | |
557 | depends on CGROUPS | |
558 | help | |
559 | Provides a simple Resource Controller for monitoring the | |
560 | total CPU consumed by the tasks in a cgroup. | |
561 | ||
562 | config RESOURCE_COUNTERS | |
563 | bool "Resource counters" | |
564 | help | |
565 | This option enables controller independent resource accounting | |
566 | infrastructure that works with cgroups. | |
567 | depends on CGROUPS | |
568 | ||
569 | config CGROUP_MEM_RES_CTLR | |
570 | bool "Memory Resource Controller for Control Groups" | |
571 | depends on CGROUPS && RESOURCE_COUNTERS | |
572 | select MM_OWNER | |
573 | help | |
574 | Provides a memory resource controller that manages both anonymous | |
575 | memory and page cache. (See Documentation/cgroups/memory.txt) | |
576 | ||
577 | Note that setting this option increases fixed memory overhead | |
578 | associated with each page of memory in the system. By this, | |
579 | 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory | |
580 | usage tracking struct at boot. Total amount of this is printed out | |
581 | at boot. | |
582 | ||
583 | Only enable when you're ok with these trade offs and really | |
584 | sure you need the memory resource controller. Even when you enable | |
585 | this, you can set "cgroup_disable=memory" at your boot option to | |
586 | disable memory resource controller and you can avoid overheads. | |
587 | (and lose benefits of memory resource controller) | |
588 | ||
589 | This config option also selects MM_OWNER config option, which | |
590 | could in turn add some fork/exit overhead. | |
591 | ||
592 | config CGROUP_MEM_RES_CTLR_SWAP | |
593 | bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)" | |
594 | depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL | |
595 | help | |
596 | Add swap management feature to memory resource controller. When you | |
597 | enable this, you can limit mem+swap usage per cgroup. In other words, | |
598 | when you disable this, memory resource controller has no cares to | |
599 | usage of swap...a process can exhaust all of the swap. This extension | |
600 | is useful when you want to avoid exhaustion swap but this itself | |
601 | adds more overheads and consumes memory for remembering information. | |
602 | Especially if you use 32bit system or small memory system, please | |
603 | be careful about enabling this. When memory resource controller | |
604 | is disabled by boot option, this will be automatically disabled and | |
605 | there will be no overhead from this. Even when you set this config=y, | |
606 | if boot option "noswapaccount" is set, swap will not be accounted. | |
607 | Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page | |
608 | size is 4096bytes, 512k per 1Gbytes of swap. | |
609 | ||
610 | endif # CGROUPS | |
611 | ||
612 | config MM_OWNER | |
613 | bool | |
614 | ||
615 | config SYSFS_DEPRECATED | |
616 | bool | |
617 | ||
618 | config SYSFS_DEPRECATED_V2 | |
619 | bool "remove sysfs features which may confuse old userspace tools" | |
620 | depends on SYSFS | |
621 | default n | |
622 | select SYSFS_DEPRECATED | |
623 | help | |
624 | This option switches the layout of sysfs to the deprecated | |
625 | version. Do not use it on recent distributions. | |
626 | ||
627 | The current sysfs layout features a unified device tree at | |
628 | /sys/devices/, which is able to express a hierarchy between | |
629 | class devices. If the deprecated option is set to Y, the | |
630 | unified device tree is split into a bus device tree at | |
631 | /sys/devices/ and several individual class device trees at | |
632 | /sys/class/. The class and bus devices will be connected by | |
633 | "<subsystem>:<name>" and the "device" links. The "block" | |
634 | class devices, will not show up in /sys/class/block/. Some | |
635 | subsystems will suppress the creation of some devices which | |
636 | depend on the unified device tree. | |
637 | ||
638 | This option is not a pure compatibility option that can | |
639 | be safely enabled on newer distributions. It will change the | |
640 | layout of sysfs to the non-extensible deprecated version, | |
641 | and disable some features, which can not be exported without | |
642 | confusing older userspace tools. Since 2007/2008 all major | |
643 | distributions do not enable this option, and ship no tools which | |
644 | depend on the deprecated layout or this option. | |
645 | ||
646 | If you are using a new kernel on an older distribution, or use | |
647 | older userspace tools, you might need to say Y here. Do not say Y, | |
648 | if the original kernel, that came with your distribution, has | |
649 | this option set to N. | |
650 | ||
651 | config RELAY | |
652 | bool "Kernel->user space relay support (formerly relayfs)" | |
653 | help | |
654 | This option enables support for relay interface support in | |
655 | certain file systems (such as debugfs). | |
656 | It is designed to provide an efficient mechanism for tools and | |
657 | facilities to relay large amounts of data from kernel space to | |
658 | user space. | |
659 | ||
660 | If unsure, say N. | |
661 | ||
662 | config NAMESPACES | |
663 | bool "Namespaces support" if EMBEDDED | |
664 | default !EMBEDDED | |
665 | help | |
666 | Provides the way to make tasks work with different objects using | |
667 | the same id. For example same IPC id may refer to different objects | |
668 | or same user id or pid may refer to different tasks when used in | |
669 | different namespaces. | |
670 | ||
671 | config UTS_NS | |
672 | bool "UTS namespace" | |
673 | depends on NAMESPACES | |
674 | help | |
675 | In this namespace tasks see different info provided with the | |
676 | uname() system call | |
677 | ||
678 | config IPC_NS | |
679 | bool "IPC namespace" | |
680 | depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE) | |
681 | help | |
682 | In this namespace tasks work with IPC ids which correspond to | |
683 | different IPC objects in different namespaces. | |
684 | ||
685 | config USER_NS | |
686 | bool "User namespace (EXPERIMENTAL)" | |
687 | depends on NAMESPACES && EXPERIMENTAL | |
688 | help | |
689 | This allows containers, i.e. vservers, to use user namespaces | |
690 | to provide different user info for different servers. | |
691 | If unsure, say N. | |
692 | ||
693 | config PID_NS | |
694 | bool "PID Namespaces (EXPERIMENTAL)" | |
695 | default n | |
696 | depends on NAMESPACES && EXPERIMENTAL | |
697 | help | |
698 | Support process id namespaces. This allows having multiple | |
699 | processes with the same pid as long as they are in different | |
700 | pid namespaces. This is a building block of containers. | |
701 | ||
702 | Unless you want to work with an experimental feature | |
703 | say N here. | |
704 | ||
705 | config NET_NS | |
706 | bool "Network namespace" | |
707 | default n | |
708 | depends on NAMESPACES && EXPERIMENTAL && NET | |
709 | help | |
710 | Allow user space to create what appear to be multiple instances | |
711 | of the network stack. | |
712 | ||
713 | config BLK_DEV_INITRD | |
714 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | |
715 | depends on BROKEN || !FRV | |
716 | help | |
717 | The initial RAM filesystem is a ramfs which is loaded by the | |
718 | boot loader (loadlin or lilo) and that is mounted as root | |
719 | before the normal boot procedure. It is typically used to | |
720 | load modules needed to mount the "real" root file system, | |
721 | etc. See <file:Documentation/initrd.txt> for details. | |
722 | ||
723 | If RAM disk support (BLK_DEV_RAM) is also included, this | |
724 | also enables initial RAM disk (initrd) support and adds | |
725 | 15 Kbytes (more on some other architectures) to the kernel size. | |
726 | ||
727 | If unsure say Y. | |
728 | ||
729 | if BLK_DEV_INITRD | |
730 | ||
731 | source "usr/Kconfig" | |
732 | ||
733 | endif | |
734 | ||
735 | config CC_OPTIMIZE_FOR_SIZE | |
736 | bool "Optimize for size" | |
737 | default y | |
738 | help | |
739 | Enabling this option will pass "-Os" instead of "-O2" to gcc | |
740 | resulting in a smaller kernel. | |
741 | ||
742 | If unsure, say Y. | |
743 | ||
744 | config SYSCTL | |
745 | bool | |
746 | ||
747 | config ANON_INODES | |
748 | bool | |
749 | ||
750 | menuconfig EMBEDDED | |
751 | bool "Configure standard kernel features (for small systems)" | |
752 | help | |
753 | This option allows certain base kernel options and settings | |
754 | to be disabled or tweaked. This is for specialized | |
755 | environments which can tolerate a "non-standard" kernel. | |
756 | Only use this if you really know what you are doing. | |
757 | ||
758 | config UID16 | |
759 | bool "Enable 16-bit UID system calls" if EMBEDDED | |
760 | depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) | |
761 | default y | |
762 | help | |
763 | This enables the legacy 16-bit UID syscall wrappers. | |
764 | ||
765 | config SYSCTL_SYSCALL | |
766 | bool "Sysctl syscall support" if EMBEDDED | |
767 | default y | |
768 | select SYSCTL | |
769 | ---help--- | |
770 | sys_sysctl uses binary paths that have been found challenging | |
771 | to properly maintain and use. The interface in /proc/sys | |
772 | using paths with ascii names is now the primary path to this | |
773 | information. | |
774 | ||
775 | Almost nothing using the binary sysctl interface so if you are | |
776 | trying to save some space it is probably safe to disable this, | |
777 | making your kernel marginally smaller. | |
778 | ||
779 | If unsure say Y here. | |
780 | ||
781 | config KALLSYMS | |
782 | bool "Load all symbols for debugging/ksymoops" if EMBEDDED | |
783 | default y | |
784 | help | |
785 | Say Y here to let the kernel print out symbolic crash information and | |
786 | symbolic stack backtraces. This increases the size of the kernel | |
787 | somewhat, as all symbols have to be loaded into the kernel image. | |
788 | ||
789 | config KALLSYMS_ALL | |
790 | bool "Include all symbols in kallsyms" | |
791 | depends on DEBUG_KERNEL && KALLSYMS | |
792 | help | |
793 | Normally kallsyms only contains the symbols of functions, for nicer | |
794 | OOPS messages. Some debuggers can use kallsyms for other | |
795 | symbols too: say Y here to include all symbols, if you need them | |
796 | and you don't care about adding 300k to the size of your kernel. | |
797 | ||
798 | Say N. | |
799 | ||
800 | config KALLSYMS_EXTRA_PASS | |
801 | bool "Do an extra kallsyms pass" | |
802 | depends on KALLSYMS | |
803 | help | |
804 | If kallsyms is not working correctly, the build will fail with | |
805 | inconsistent kallsyms data. If that occurs, log a bug report and | |
806 | turn on KALLSYMS_EXTRA_PASS which should result in a stable build. | |
807 | Always say N here unless you find a bug in kallsyms, which must be | |
808 | reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while | |
809 | you wait for kallsyms to be fixed. | |
810 | ||
811 | ||
812 | config HOTPLUG | |
813 | bool "Support for hot-pluggable devices" if EMBEDDED | |
814 | default y | |
815 | help | |
816 | This option is provided for the case where no hotplug or uevent | |
817 | capabilities is wanted by the kernel. You should only consider | |
818 | disabling this option for embedded systems that do not use modules, a | |
819 | dynamic /dev tree, or dynamic device discovery. Just say Y. | |
820 | ||
821 | config PRINTK | |
822 | default y | |
823 | bool "Enable support for printk" if EMBEDDED | |
824 | help | |
825 | This option enables normal printk support. Removing it | |
826 | eliminates most of the message strings from the kernel image | |
827 | and makes the kernel more or less silent. As this makes it | |
828 | very difficult to diagnose system problems, saying N here is | |
829 | strongly discouraged. | |
830 | ||
831 | config BUG | |
832 | bool "BUG() support" if EMBEDDED | |
833 | default y | |
834 | help | |
835 | Disabling this option eliminates support for BUG and WARN, reducing | |
836 | the size of your kernel image and potentially quietly ignoring | |
837 | numerous fatal conditions. You should only consider disabling this | |
838 | option for embedded systems with no facilities for reporting errors. | |
839 | Just say Y. | |
840 | ||
841 | config ELF_CORE | |
842 | default y | |
843 | bool "Enable ELF core dumps" if EMBEDDED | |
844 | help | |
845 | Enable support for generating core dumps. Disabling saves about 4k. | |
846 | ||
847 | config PCSPKR_PLATFORM | |
848 | bool "Enable PC-Speaker support" if EMBEDDED | |
849 | depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES | |
850 | default y | |
851 | help | |
852 | This option allows to disable the internal PC-Speaker | |
853 | support, saving some memory. | |
854 | ||
855 | config BASE_FULL | |
856 | default y | |
857 | bool "Enable full-sized data structures for core" if EMBEDDED | |
858 | help | |
859 | Disabling this option reduces the size of miscellaneous core | |
860 | kernel data structures. This saves memory on small machines, | |
861 | but may reduce performance. | |
862 | ||
863 | config FUTEX | |
864 | bool "Enable futex support" if EMBEDDED | |
865 | default y | |
866 | select RT_MUTEXES | |
867 | help | |
868 | Disabling this option will cause the kernel to be built without | |
869 | support for "fast userspace mutexes". The resulting kernel may not | |
870 | run glibc-based applications correctly. | |
871 | ||
872 | config EPOLL | |
873 | bool "Enable eventpoll support" if EMBEDDED | |
874 | default y | |
875 | select ANON_INODES | |
876 | help | |
877 | Disabling this option will cause the kernel to be built without | |
878 | support for epoll family of system calls. | |
879 | ||
880 | config SIGNALFD | |
881 | bool "Enable signalfd() system call" if EMBEDDED | |
882 | select ANON_INODES | |
883 | default y | |
884 | help | |
885 | Enable the signalfd() system call that allows to receive signals | |
886 | on a file descriptor. | |
887 | ||
888 | If unsure, say Y. | |
889 | ||
890 | config TIMERFD | |
891 | bool "Enable timerfd() system call" if EMBEDDED | |
892 | select ANON_INODES | |
893 | default y | |
894 | help | |
895 | Enable the timerfd() system call that allows to receive timer | |
896 | events on a file descriptor. | |
897 | ||
898 | If unsure, say Y. | |
899 | ||
900 | config EVENTFD | |
901 | bool "Enable eventfd() system call" if EMBEDDED | |
902 | select ANON_INODES | |
903 | default y | |
904 | help | |
905 | Enable the eventfd() system call that allows to receive both | |
906 | kernel notification (ie. KAIO) or userspace notifications. | |
907 | ||
908 | If unsure, say Y. | |
909 | ||
910 | config SHMEM | |
911 | bool "Use full shmem filesystem" if EMBEDDED | |
912 | default y | |
913 | depends on MMU | |
914 | help | |
915 | The shmem is an internal filesystem used to manage shared memory. | |
916 | It is backed by swap and manages resource limits. It is also exported | |
917 | to userspace as tmpfs if TMPFS is enabled. Disabling this | |
918 | option replaces shmem and tmpfs with the much simpler ramfs code, | |
919 | which may be appropriate on small systems without swap. | |
920 | ||
921 | config AIO | |
922 | bool "Enable AIO support" if EMBEDDED | |
923 | default y | |
924 | help | |
925 | This option enables POSIX asynchronous I/O which may by used | |
926 | by some high performance threaded applications. Disabling | |
927 | this option saves about 7k. | |
928 | ||
929 | config HAVE_PERF_COUNTERS | |
930 | bool | |
931 | help | |
932 | See tools/perf/design.txt for details. | |
933 | ||
934 | menu "Performance Counters" | |
935 | ||
936 | config PERF_COUNTERS | |
937 | bool "Kernel Performance Counters" | |
938 | depends on HAVE_PERF_COUNTERS | |
939 | select ANON_INODES | |
940 | help | |
941 | Enable kernel support for performance counter hardware. | |
942 | ||
943 | Performance counters are special hardware registers available | |
944 | on most modern CPUs. These registers count the number of certain | |
945 | types of hw events: such as instructions executed, cachemisses | |
946 | suffered, or branches mis-predicted - without slowing down the | |
947 | kernel or applications. These registers can also trigger interrupts | |
948 | when a threshold number of events have passed - and can thus be | |
949 | used to profile the code that runs on that CPU. | |
950 | ||
951 | The Linux Performance Counter subsystem provides an abstraction of | |
952 | these hardware capabilities, available via a system call. It | |
953 | provides per task and per CPU counters, and it provides event | |
954 | capabilities on top of those. | |
955 | ||
956 | Say Y if unsure. | |
957 | ||
958 | config EVENT_PROFILE | |
959 | bool "Tracepoint profile sources" | |
960 | depends on PERF_COUNTERS && EVENT_TRACER | |
961 | default y | |
962 | ||
963 | endmenu | |
964 | ||
965 | config VM_EVENT_COUNTERS | |
966 | default y | |
967 | bool "Enable VM event counters for /proc/vmstat" if EMBEDDED | |
968 | help | |
969 | VM event counters are needed for event counts to be shown. | |
970 | This option allows the disabling of the VM event counters | |
971 | on EMBEDDED systems. /proc/vmstat will only show page counts | |
972 | if VM event counters are disabled. | |
973 | ||
974 | config PCI_QUIRKS | |
975 | default y | |
976 | bool "Enable PCI quirk workarounds" if EMBEDDED | |
977 | depends on PCI | |
978 | help | |
979 | This enables workarounds for various PCI chipset | |
980 | bugs/quirks. Disable this only if your target machine is | |
981 | unaffected by PCI quirks. | |
982 | ||
983 | config SLUB_DEBUG | |
984 | default y | |
985 | bool "Enable SLUB debugging support" if EMBEDDED | |
986 | depends on SLUB && SYSFS | |
987 | help | |
988 | SLUB has extensive debug support features. Disabling these can | |
989 | result in significant savings in code size. This also disables | |
990 | SLUB sysfs support. /sys/slab will not exist and there will be | |
991 | no support for cache validation etc. | |
992 | ||
993 | config STRIP_ASM_SYMS | |
994 | bool "Strip assembler-generated symbols during link" | |
995 | default n | |
996 | help | |
997 | Strip internal assembler-generated symbols during a link (symbols | |
998 | that look like '.Lxxx') so they don't pollute the output of | |
999 | get_wchan() and suchlike. | |
1000 | ||
1001 | config COMPAT_BRK | |
1002 | bool "Disable heap randomization" | |
1003 | default y | |
1004 | help | |
1005 | Randomizing heap placement makes heap exploits harder, but it | |
1006 | also breaks ancient binaries (including anything libc5 based). | |
1007 | This option changes the bootup default to heap randomization | |
1008 | disabled, and can be overridden at runtime by setting | |
1009 | /proc/sys/kernel/randomize_va_space to 2. | |
1010 | ||
1011 | On non-ancient distros (post-2000 ones) N is usually a safe choice. | |
1012 | ||
1013 | choice | |
1014 | prompt "Choose SLAB allocator" | |
1015 | default SLUB | |
1016 | help | |
1017 | This option allows to select a slab allocator. | |
1018 | ||
1019 | config SLAB | |
1020 | bool "SLAB" | |
1021 | help | |
1022 | The regular slab allocator that is established and known to work | |
1023 | well in all environments. It organizes cache hot objects in | |
1024 | per cpu and per node queues. | |
1025 | ||
1026 | config SLUB | |
1027 | bool "SLUB (Unqueued Allocator)" | |
1028 | help | |
1029 | SLUB is a slab allocator that minimizes cache line usage | |
1030 | instead of managing queues of cached objects (SLAB approach). | |
1031 | Per cpu caching is realized using slabs of objects instead | |
1032 | of queues of objects. SLUB can use memory efficiently | |
1033 | and has enhanced diagnostics. SLUB is the default choice for | |
1034 | a slab allocator. | |
1035 | ||
1036 | config SLOB | |
1037 | depends on EMBEDDED | |
1038 | bool "SLOB (Simple Allocator)" | |
1039 | help | |
1040 | SLOB replaces the stock allocator with a drastically simpler | |
1041 | allocator. SLOB is generally more space efficient but | |
1042 | does not perform as well on large systems. | |
1043 | ||
1044 | endchoice | |
1045 | ||
1046 | config PROFILING | |
1047 | bool "Profiling support (EXPERIMENTAL)" | |
1048 | help | |
1049 | Say Y here to enable the extended profiling support mechanisms used | |
1050 | by profilers such as OProfile. | |
1051 | ||
1052 | # | |
1053 | # Place an empty function call at each tracepoint site. Can be | |
1054 | # dynamically changed for a probe function. | |
1055 | # | |
1056 | config TRACEPOINTS | |
1057 | bool | |
1058 | ||
1059 | config MARKERS | |
1060 | bool "Activate markers" | |
1061 | select TRACEPOINTS | |
1062 | help | |
1063 | Place an empty function call at each marker site. Can be | |
1064 | dynamically changed for a probe function. | |
1065 | ||
1066 | source "arch/Kconfig" | |
1067 | ||
1068 | config SLOW_WORK | |
1069 | default n | |
1070 | bool | |
1071 | help | |
1072 | The slow work thread pool provides a number of dynamically allocated | |
1073 | threads that can be used by the kernel to perform operations that | |
1074 | take a relatively long time. | |
1075 | ||
1076 | An example of this would be CacheFiles doing a path lookup followed | |
1077 | by a series of mkdirs and a create call, all of which have to touch | |
1078 | disk. | |
1079 | ||
1080 | See Documentation/slow-work.txt. | |
1081 | ||
1082 | endmenu # General setup | |
1083 | ||
1084 | config HAVE_GENERIC_DMA_COHERENT | |
1085 | bool | |
1086 | default n | |
1087 | ||
1088 | config SLABINFO | |
1089 | bool | |
1090 | depends on PROC_FS | |
1091 | depends on SLAB || SLUB_DEBUG | |
1092 | default y | |
1093 | ||
1094 | config RT_MUTEXES | |
1095 | boolean | |
1096 | ||
1097 | config BASE_SMALL | |
1098 | int | |
1099 | default 0 if BASE_FULL | |
1100 | default 1 if !BASE_FULL | |
1101 | ||
1102 | menuconfig MODULES | |
1103 | bool "Enable loadable module support" | |
1104 | help | |
1105 | Kernel modules are small pieces of compiled code which can | |
1106 | be inserted in the running kernel, rather than being | |
1107 | permanently built into the kernel. You use the "modprobe" | |
1108 | tool to add (and sometimes remove) them. If you say Y here, | |
1109 | many parts of the kernel can be built as modules (by | |
1110 | answering M instead of Y where indicated): this is most | |
1111 | useful for infrequently used options which are not required | |
1112 | for booting. For more information, see the man pages for | |
1113 | modprobe, lsmod, modinfo, insmod and rmmod. | |
1114 | ||
1115 | If you say Y here, you will need to run "make | |
1116 | modules_install" to put the modules under /lib/modules/ | |
1117 | where modprobe can find them (you may need to be root to do | |
1118 | this). | |
1119 | ||
1120 | If unsure, say Y. | |
1121 | ||
1122 | if MODULES | |
1123 | ||
1124 | config MODULE_FORCE_LOAD | |
1125 | bool "Forced module loading" | |
1126 | default n | |
1127 | help | |
1128 | Allow loading of modules without version information (ie. modprobe | |
1129 | --force). Forced module loading sets the 'F' (forced) taint flag and | |
1130 | is usually a really bad idea. | |
1131 | ||
1132 | config MODULE_UNLOAD | |
1133 | bool "Module unloading" | |
1134 | help | |
1135 | Without this option you will not be able to unload any | |
1136 | modules (note that some modules may not be unloadable | |
1137 | anyway), which makes your kernel smaller, faster | |
1138 | and simpler. If unsure, say Y. | |
1139 | ||
1140 | config MODULE_FORCE_UNLOAD | |
1141 | bool "Forced module unloading" | |
1142 | depends on MODULE_UNLOAD && EXPERIMENTAL | |
1143 | help | |
1144 | This option allows you to force a module to unload, even if the | |
1145 | kernel believes it is unsafe: the kernel will remove the module | |
1146 | without waiting for anyone to stop using it (using the -f option to | |
1147 | rmmod). This is mainly for kernel developers and desperate users. | |
1148 | If unsure, say N. | |
1149 | ||
1150 | config MODVERSIONS | |
1151 | bool "Module versioning support" | |
1152 | help | |
1153 | Usually, you have to use modules compiled with your kernel. | |
1154 | Saying Y here makes it sometimes possible to use modules | |
1155 | compiled for different kernels, by adding enough information | |
1156 | to the modules to (hopefully) spot any changes which would | |
1157 | make them incompatible with the kernel you are running. If | |
1158 | unsure, say N. | |
1159 | ||
1160 | config MODULE_SRCVERSION_ALL | |
1161 | bool "Source checksum for all modules" | |
1162 | help | |
1163 | Modules which contain a MODULE_VERSION get an extra "srcversion" | |
1164 | field inserted into their modinfo section, which contains a | |
1165 | sum of the source files which made it. This helps maintainers | |
1166 | see exactly which source was used to build a module (since | |
1167 | others sometimes change the module source without updating | |
1168 | the version). With this option, such a "srcversion" field | |
1169 | will be created for all modules. If unsure, say N. | |
1170 | ||
1171 | endif # MODULES | |
1172 | ||
1173 | config INIT_ALL_POSSIBLE | |
1174 | bool | |
1175 | help | |
1176 | Back when each arch used to define their own cpu_online_map and | |
1177 | cpu_possible_map, some of them chose to initialize cpu_possible_map | |
1178 | with all 1s, and others with all 0s. When they were centralised, | |
1179 | it was better to provide this option than to break all the archs | |
1180 | and have several arch maintainers pursuing me down dark alleys. | |
1181 | ||
1182 | config STOP_MACHINE | |
1183 | bool | |
1184 | default y | |
1185 | depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU | |
1186 | help | |
1187 | Need stop_machine() primitive. | |
1188 | ||
1189 | source "block/Kconfig" | |
1190 | ||
1191 | config PREEMPT_NOTIFIERS | |
1192 | bool | |
1193 |