build: make the squashfs block size configurable
[openwrt/openwrt.git] / config / Config-kernel.in
1 # Copyright (C) 2006-2014 OpenWrt.org
2 #
3 # This is free software, licensed under the GNU General Public License v2.
4 # See /LICENSE for more information.
5 #
6
7 config KERNEL_PRINTK
8 bool "Enable support for printk"
9 default y
10
11 config KERNEL_CRASHLOG
12 bool "Crash logging"
13 depends on !(arm || powerpc || sparc)
14 default y
15
16 config KERNEL_SWAP
17 bool "Support for paging of anonymous memory (swap)"
18 default y
19
20 config KERNEL_DEBUG_FS
21 bool "Compile the kernel with Debug FileSystem enabled"
22 default y
23 help
24 debugfs is a virtual file system that kernel developers use to put
25 debugging files into. Enable this option to be able to read and
26 write to these files.
27
28 config KERNEL_PERF_EVENTS
29 bool
30 default n
31
32 config KERNEL_PROFILING
33 bool "Compile the kernel with profiling enabled"
34 default n
35 select KERNEL_PERF_EVENTS
36 help
37 Enable the extended profiling support mechanisms used by profilers such
38 as OProfile.
39
40 config KERNEL_KALLSYMS
41 bool "Compile the kernel with symbol table information"
42 default y
43 help
44 This will give you more information in stack traces from kernel oopses
45
46 config KERNEL_FTRACE
47 bool "Compile the kernel with tracing support"
48 default n
49
50 config KERNEL_FTRACE_SYSCALLS
51 bool "Trace system calls"
52 depends on KERNEL_FTRACE
53 default n
54
55 config KERNEL_ENABLE_DEFAULT_TRACERS
56 bool "Trace process context switches and events"
57 depends on KERNEL_FTRACE
58 default n
59
60 config KERNEL_DEBUG_KERNEL
61 bool
62 default n
63
64 config KERNEL_DEBUG_INFO
65 bool "Compile the kernel with debug information"
66 default y
67 select KERNEL_DEBUG_KERNEL
68 help
69 This will compile your kernel and modules with debug information.
70
71 config KERNEL_DEBUG_LL_UART_NONE
72 bool
73 default n
74 depends on arm
75
76 config KERNEL_DEBUG_LL
77 bool
78 default n
79 depends on arm
80 select KERNEL_DEBUG_LL_UART_NONE
81 help
82 ARM low level debugging
83
84 config KERNEL_DYNAMIC_DEBUG
85 bool "Compile the kernel with dynamic printk"
86 select KERNEL_DEBUG_FS
87 default n
88 help
89 Compiles debug level messages into the kernel, which would not
90 otherwise be available at runtime. These messages can then be
91 enabled/disabled based on various levels of scope - per source file,
92 function, module, format string, and line number. This mechanism
93 implicitly compiles in all pr_debug() and dev_dbg() calls, which
94 enlarges the kernel text size by about 2%.
95
96 config KERNEL_EARLY_PRINTK
97 bool "Compile the kernel with early printk"
98 default n
99 depends on arm
100 select KERNEL_DEBUG_KERNEL
101 select KERNEL_DEBUG_LL if arm
102 help
103 Compile the kernel with early printk support.
104 This is only useful for debugging purposes to send messages
105 over the serial console in early boot.
106 Enable this to debug early boot problems.
107
108 config KERNEL_AIO
109 bool "Compile the kernel with asynchronous IO support"
110 default n
111
112 config KERNEL_DIRECT_IO
113 bool "Compile the kernel with direct IO support"
114 default n
115
116 config KERNEL_MAGIC_SYSRQ
117 bool "Compile the kernel with SysRq support"
118 default y
119
120 config KERNEL_COREDUMP
121 bool
122
123 config KERNEL_ELF_CORE
124 bool "Enable process core dump support"
125 select KERNEL_COREDUMP
126 default y
127
128 config KERNEL_PROVE_LOCKING
129 bool "Enable kernel lock checking"
130 select KERNEL_DEBUG_KERNEL
131 default n
132
133 config KERNEL_PRINTK_TIME
134 bool "Enable printk timestamps"
135 default y
136
137 config KERNEL_SLUB_DEBUG
138 bool
139
140 config KERNEL_SLUB_DEBUG_ON
141 bool
142
143 config KERNEL_SLABINFO
144 select KERNEL_SLUB_DEBUG
145 select KERNEL_SLUB_DEBUG_ON
146 bool "Enable /proc slab debug info"
147
148 config KERNEL_PROC_PAGE_MONITOR
149 bool "Enable /proc page monitoring"
150
151 config KERNEL_RELAY
152 bool
153
154 config KERNEL_KEXEC
155 bool "Enable kexec support"
156
157 config USE_RFKILL
158 bool "Enable rfkill support"
159 default RFKILL_SUPPORT
160
161 config USE_SPARSE
162 bool "Enable sparse check during kernel build"
163 default n
164
165 #
166 # CGROUP support symbols
167 #
168
169 config KERNEL_CGROUPS
170 bool "Enable kernel cgroups"
171 default n
172
173 if KERNEL_CGROUPS
174
175 config KERNEL_CGROUP_DEBUG
176 bool "Example debug cgroup subsystem"
177 default n
178 help
179 This option enables a simple cgroup subsystem that
180 exports useful debugging information about the cgroups
181 framework.
182
183 config KERNEL_FREEZER
184 bool
185 default y if KERNEL_CGROUP_FREEZER
186
187 config KERNEL_CGROUP_FREEZER
188 bool "Freezer cgroup subsystem"
189 default n
190 help
191 Provides a way to freeze and unfreeze all tasks in a
192 cgroup.
193
194 config KERNEL_CGROUP_DEVICE
195 bool "Device controller for cgroups"
196 default y
197 help
198 Provides a cgroup implementing whitelists for devices which
199 a process in the cgroup can mknod or open.
200
201 config KERNEL_CPUSETS
202 bool "Cpuset support"
203 default n
204 help
205 This option will let you create and manage CPUSETs which
206 allow dynamically partitioning a system into sets of CPUs and
207 Memory Nodes and assigning tasks to run only within those sets.
208 This is primarily useful on large SMP or NUMA systems.
209
210 config KERNEL_PROC_PID_CPUSET
211 bool "Include legacy /proc/<pid>/cpuset file"
212 default n
213 depends on KERNEL_CPUSETS
214
215 config KERNEL_CGROUP_CPUACCT
216 bool "Simple CPU accounting cgroup subsystem"
217 default n
218 help
219 Provides a simple Resource Controller for monitoring the
220 total CPU consumed by the tasks in a cgroup.
221
222 config KERNEL_RESOURCE_COUNTERS
223 bool "Resource counters"
224 default n
225 help
226 This option enables controller independent resource accounting
227 infrastructure that works with cgroups.
228
229 config KERNEL_MM_OWNER
230 bool
231 default y if KERNEL_MEMCG
232
233 config KERNEL_MEMCG
234 bool "Memory Resource Controller for Control Groups"
235 default n
236 depends on KERNEL_RESOURCE_COUNTERS
237 help
238 Provides a memory resource controller that manages both anonymous
239 memory and page cache. (See Documentation/cgroups/memory.txt)
240
241 Note that setting this option increases fixed memory overhead
242 associated with each page of memory in the system. By this,
243 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
244 usage tracking struct at boot. Total amount of this is printed out
245 at boot.
246
247 Only enable when you're ok with these trade offs and really
248 sure you need the memory resource controller. Even when you enable
249 this, you can set "cgroup_disable=memory" at your boot option to
250 disable memory resource controller and you can avoid overheads.
251 (and lose benefits of memory resource controller)
252
253 This config option also selects MM_OWNER config option, which
254 could in turn add some fork/exit overhead.
255
256 config KERNEL_MEMCG_SWAP
257 bool "Memory Resource Controller Swap Extension"
258 default n
259 depends on KERNEL_MEMCG
260 help
261 Add swap management feature to memory resource controller. When you
262 enable this, you can limit mem+swap usage per cgroup. In other words,
263 when you disable this, memory resource controller has no cares to
264 usage of swap...a process can exhaust all of the swap. This extension
265 is useful when you want to avoid exhaustion swap but this itself
266 adds more overheads and consumes memory for remembering information.
267 Especially if you use 32bit system or small memory system, please
268 be careful about enabling this. When memory resource controller
269 is disabled by boot option, this will be automatically disabled and
270 there will be no overhead from this. Even when you set this config=y,
271 if boot option "swapaccount=0" is set, swap will not be accounted.
272 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
273 size is 4096bytes, 512k per 1Gbytes of swap.
274
275 config KERNEL_MEMCG_SWAP_ENABLED
276 bool "Memory Resource Controller Swap Extension enabled by default"
277 default n
278 depends on KERNEL_MEMCG_SWAP
279 help
280 Memory Resource Controller Swap Extension comes with its price in
281 a bigger memory consumption. General purpose distribution kernels
282 which want to enable the feature but keep it disabled by default
283 and let the user enable it by swapaccount boot command line
284 parameter should have this option unselected.
285 For those who want to have the feature enabled by default should
286 select this option (if, for some reason, they need to disable it
287 then swapaccount=0 does the trick).
288
289
290 config KERNEL_MEMCG_KMEM
291 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
292 default n
293 depends on KERNEL_MEMCG
294 help
295 The Kernel Memory extension for Memory Resource Controller can limit
296 the amount of memory used by kernel objects in the system. Those are
297 fundamentally different from the entities handled by the standard
298 Memory Controller, which are page-based, and can be swapped. Users of
299 the kmem extension can use it to guarantee that no group of processes
300 will ever exhaust kernel resources alone.
301
302 config KERNEL_PERF_EVENTS
303 bool
304 default y if KERNEL_CGROUP_PERF
305
306 config KERNEL_CGROUP_PERF
307 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
308 default n
309 help
310 This option extends the per-cpu mode to restrict monitoring to
311 threads which belong to the cgroup specified and run on the
312 designated cpu.
313
314 menuconfig KERNEL_CGROUP_SCHED
315 bool "Group CPU scheduler"
316 default n
317 help
318 This feature lets CPU scheduler recognize task groups and control CPU
319 bandwidth allocation to such task groups. It uses cgroups to group
320 tasks.
321
322 if KERNEL_CGROUP_SCHED
323
324 config KERNEL_FAIR_GROUP_SCHED
325 bool "Group scheduling for SCHED_OTHER"
326 default n
327
328 config KERNEL_CFS_BANDWIDTH
329 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
330 default n
331 depends on KERNEL_FAIR_GROUP_SCHED
332 help
333 This option allows users to define CPU bandwidth rates (limits) for
334 tasks running within the fair group scheduler. Groups with no limit
335 set are considered to be unconstrained and will run with no
336 restriction.
337 See tip/Documentation/scheduler/sched-bwc.txt for more information.
338
339 config KERNEL_RT_GROUP_SCHED
340 bool "Group scheduling for SCHED_RR/FIFO"
341 default n
342 help
343 This feature lets you explicitly allocate real CPU bandwidth
344 to task groups. If enabled, it will also make it impossible to
345 schedule realtime tasks for non-root users until you allocate
346 realtime bandwidth for them.
347
348 endif
349
350 config KERNEL_BLK_CGROUP
351 bool "Block IO controller"
352 default y
353 help
354 Generic block IO controller cgroup interface. This is the common
355 cgroup interface which should be used by various IO controlling
356 policies.
357
358 Currently, CFQ IO scheduler uses it to recognize task groups and
359 control disk bandwidth allocation (proportional time slice allocation)
360 to such task groups. It is also used by bio throttling logic in
361 block layer to implement upper limit in IO rates on a device.
362
363 This option only enables generic Block IO controller infrastructure.
364 One needs to also enable actual IO controlling logic/policy. For
365 enabling proportional weight division of disk bandwidth in CFQ, set
366 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
367 CONFIG_BLK_DEV_THROTTLING=y.
368
369 config KERNEL_DEBUG_BLK_CGROUP
370 bool "Enable Block IO controller debugging"
371 default n
372 depends on KERNEL_BLK_CGROUP
373 help
374 Enable some debugging help. Currently it exports additional stat
375 files in a cgroup which can be useful for debugging.
376
377 config KERNEL_NET_CLS_CGROUP
378 bool "Control Group Classifier"
379 default y
380
381 config KERNEL_NETPRIO_CGROUP
382 bool "Network priority cgroup"
383 default y
384
385 endif
386
387 #
388 # Namespace support symbols
389 #
390
391 config KERNEL_NAMESPACES
392 bool "Enable kernel namespaces"
393 default n
394
395 if KERNEL_NAMESPACES
396
397 config KERNEL_UTS_NS
398 bool "UTS namespace"
399 default y
400 help
401 In this namespace tasks see different info provided
402 with the uname() system call
403
404 config KERNEL_IPC_NS
405 bool "IPC namespace"
406 default y
407 help
408 In this namespace tasks work with IPC ids which correspond to
409 different IPC objects in different namespaces.
410
411 config KERNEL_USER_NS
412 bool "User namespace (EXPERIMENTAL)"
413 default y
414 help
415 This allows containers, i.e. vservers, to use user namespaces
416 to provide different user info for different servers.
417
418 config KERNEL_PID_NS
419 bool "PID Namespaces"
420 default y
421 help
422 Support process id namespaces. This allows having multiple
423 processes with the same pid as long as they are in different
424 pid namespaces. This is a building block of containers.
425
426 config KERNEL_NET_NS
427 bool "Network namespace"
428 default y
429 help
430 Allow user space to create what appear to be multiple instances
431 of the network stack.
432
433 endif
434
435 #
436 # LXC related symbols
437 #
438
439 config KERNEL_LXC_MISC
440 bool "Enable miscellaneous LXC related options"
441 default n
442
443 if KERNEL_LXC_MISC
444
445 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
446 bool "Support multiple instances of devpts"
447 default y
448 help
449 Enable support for multiple instances of devpts filesystem.
450 If you want to have isolated PTY namespaces (eg: in containers),
451 say Y here. Otherwise, say N. If enabled, each mount of devpts
452 filesystem with the '-o newinstance' option will create an
453 independent PTY namespace.
454
455 config KERNEL_POSIX_MQUEUE
456 bool "POSIX Message Queues"
457 default y
458 help
459 POSIX variant of message queues is a part of IPC. In POSIX message
460 queues every message has a priority which decides about succession
461 of receiving it by a process. If you want to compile and run
462 programs written e.g. for Solaris with use of its POSIX message
463 queues (functions mq_*) say Y here.
464
465 POSIX message queues are visible as a filesystem called 'mqueue'
466 and can be mounted somewhere if you want to do filesystem
467 operations on message queues.
468
469 endif