1 # SPDX-License-Identifier: GPL-2.0-only !! 1 config ARCH
2 config CC_VERSION_TEXT <<
3 string 2 string
4 default "$(CC_VERSION_TEXT)" !! 3 option env="ARCH"
5 help <<
6 This is used in unclear ways: <<
7 <<
8 - Re-run Kconfig when the compiler i <<
9 The 'default' property references <<
10 CC_VERSION_TEXT so it is recorded <<
11 When the compiler is updated, Kcon <<
12 <<
13 - Ensure full rebuild when the compi <<
14 include/linux/compiler-version.h c <<
15 line so fixdep adds include/config <<
16 auto-generated dependency. When th <<
17 will touch it and then every file <<
18 <<
19 config CC_IS_GCC <<
20 def_bool $(success,test "$(cc-name)" = <<
21 <<
22 config GCC_VERSION <<
23 int <<
24 default $(cc-version) if CC_IS_GCC <<
25 default 0 <<
26 <<
27 config CC_IS_CLANG <<
28 def_bool $(success,test "$(cc-name)" = <<
29 <<
30 config CLANG_VERSION <<
31 int <<
32 default $(cc-version) if CC_IS_CLANG <<
33 default 0 <<
34 <<
35 config AS_IS_GNU <<
36 def_bool $(success,test "$(as-name)" = <<
37 <<
38 config AS_IS_LLVM <<
39 def_bool $(success,test "$(as-name)" = <<
40 <<
41 config AS_VERSION <<
42 int <<
43 # Use clang version if this is the int <<
44 default CLANG_VERSION if AS_IS_LLVM <<
45 default $(as-version) <<
46 <<
47 config LD_IS_BFD <<
48 def_bool $(success,test "$(ld-name)" = <<
49 <<
50 config LD_VERSION <<
51 int <<
52 default $(ld-version) if LD_IS_BFD <<
53 default 0 <<
54 <<
55 config LD_IS_LLD <<
56 def_bool $(success,test "$(ld-name)" = <<
57 <<
58 config LLD_VERSION <<
59 int <<
60 default $(ld-version) if LD_IS_LLD <<
61 default 0 <<
62 <<
63 config RUSTC_VERSION <<
64 int <<
65 default $(rustc-version) <<
66 help <<
67 It does not depend on `RUST` since t <<
68 in a `depends on`. <<
69 <<
70 config RUST_IS_AVAILABLE <<
71 def_bool $(success,$(srctree)/scripts/ <<
72 help <<
73 This shows whether a suitable Rust t <<
74 <<
75 Please see Documentation/rust/quick- <<
76 to satisfy the build requirements of <<
77 <<
78 In particular, the Makefile target ' <<
79 why the Rust toolchain is not being <<
80 <<
81 config RUSTC_LLVM_VERSION <<
82 int <<
83 default $(rustc-llvm-version) <<
84 <<
85 config CC_CAN_LINK <<
86 bool <<
87 default $(success,$(srctree)/scripts/c <<
88 default $(success,$(srctree)/scripts/c <<
89 <<
90 config CC_CAN_LINK_STATIC <<
91 bool <<
92 default $(success,$(srctree)/scripts/c <<
93 default $(success,$(srctree)/scripts/c <<
94 <<
95 # Fixed in GCC 14, 13.3, 12.4 and 11.5 <<
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id <<
97 config GCC_ASM_GOTO_OUTPUT_BROKEN <<
98 bool <<
99 depends on CC_IS_GCC <<
100 default y if GCC_VERSION < 110500 <<
101 default y if GCC_VERSION >= 120000 && <<
102 default y if GCC_VERSION >= 130000 && <<
103 <<
104 config CC_HAS_ASM_GOTO_OUTPUT <<
105 def_bool y <<
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN <<
107 depends on $(success,echo 'int foo(int <<
108 <<
109 config CC_HAS_ASM_GOTO_TIED_OUTPUT <<
110 depends on CC_HAS_ASM_GOTO_OUTPUT <<
111 # Detect buggy gcc and clang, fixed in <<
112 def_bool $(success,echo 'int foo(int * <<
113 <<
114 config TOOLS_SUPPORT_RELR <<
115 def_bool $(success,env "CC=$(CC)" "LD= <<
116 4
117 config CC_HAS_ASM_INLINE !! 5 config KERNELVERSION
118 def_bool $(success,echo 'void foo(void !! 6 string
119 !! 7 option env="KERNELVERSION"
120 config CC_HAS_NO_PROFILE_FN_ATTR <<
121 def_bool $(success,echo '__attribute__ <<
122 8
123 config PAHOLE_VERSION !! 9 config DEFCONFIG_LIST
124 int !! 10 string
125 default $(shell,$(srctree)/scripts/pah !! 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"
126 18
127 config CONSTRUCTORS 19 config CONSTRUCTORS
128 bool 20 bool
>> 21 depends on !UML
129 22
130 config IRQ_WORK 23 config IRQ_WORK
131 def_bool y if SMP !! 24 bool
132 25
133 config BUILDTIME_TABLE_SORT !! 26 config BUILDTIME_EXTABLE_SORT
134 bool 27 bool
135 28
136 config THREAD_INFO_IN_TASK 29 config THREAD_INFO_IN_TASK
137 bool 30 bool
138 help 31 help
139 Select this to move thread_info off 32 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 33 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 34 except flags and fix any runtime bugs.
142 35
143 One subtle change that will be neede 36 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 37 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 38
146 menu "General setup" 39 menu "General setup"
147 40
148 config BROKEN 41 config BROKEN
149 bool 42 bool
150 43
151 config BROKEN_ON_SMP 44 config BROKEN_ON_SMP
152 bool 45 bool
153 depends on BROKEN || !SMP 46 depends on BROKEN || !SMP
154 default y 47 default y
155 48
156 config INIT_ENV_ARG_LIMIT 49 config INIT_ENV_ARG_LIMIT
157 int 50 int
158 default 32 if !UML 51 default 32 if !UML
159 default 128 if UML 52 default 128 if UML
160 help 53 help
161 Maximum of each of the number of arg 54 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 55 variables passed to init from the kernel command line.
163 56
>> 57
>> 58 config CROSS_COMPILE
>> 59 string "Cross-compiler tool prefix"
>> 60 help
>> 61 Same as running 'make CROSS_COMPILE=prefix-' but stored for
>> 62 default make runs in this kernel build directory. You don't
>> 63 need to set this unless you want the configured kernel build
>> 64 directory to select the cross-compiler automatically.
>> 65
164 config COMPILE_TEST 66 config COMPILE_TEST
165 bool "Compile also drivers which will 67 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 68 depends on HAS_IOMEM
167 help 69 help
168 Some drivers can be compiled on a di 70 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 71 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 72 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 73 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 74 drivers to compile-test them.
173 75
174 If you are a developer and want to b 76 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 77 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 78 drivers to be distributed.
177 79
178 config WERROR <<
179 bool "Compile the kernel with warnings <<
180 default COMPILE_TEST <<
181 help <<
182 A kernel build should not cause any <<
183 enables the '-Werror' (for C) and '- <<
184 to enforce that rule by default. Cer <<
185 such as the linker may be upgraded t <<
186 well. <<
187 <<
188 However, if you have a new (or very <<
189 and unusual warnings, or you have so <<
190 you may need to disable this config <<
191 successfully build the kernel. <<
192 <<
193 If in doubt, say Y. <<
194 <<
195 config UAPI_HEADER_TEST <<
196 bool "Compile test UAPI headers" <<
197 depends on HEADERS_INSTALL && CC_CAN_L <<
198 help <<
199 Compile test headers exported to use <<
200 self-contained, i.e. compilable as s <<
201 <<
202 If you are a developer or tester and <<
203 headers are self-contained, say Y he <<
204 <<
205 config LOCALVERSION 80 config LOCALVERSION
206 string "Local version - append to kern 81 string "Local version - append to kernel release"
207 help 82 help
208 Append an extra string to the end of 83 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 84 This will show up when you type uname, for example.
210 The string you set here will be appe 85 The string you set here will be appended after the contents of
211 any files with a filename matching l 86 any files with a filename matching localversion* in your
212 object and source tree, in that orde 87 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 88 be a maximum of 64 characters.
214 89
215 config LOCALVERSION_AUTO 90 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 91 bool "Automatically append version information to the version string"
217 default y 92 default y
218 depends on !COMPILE_TEST <<
219 help 93 help
220 This will try to automatically deter 94 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 95 release tree by looking for git tags that belong to the current
222 top of tree revision. 96 top of tree revision.
223 97
224 A string of the format -gxxxxxxxx wi 98 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 99 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 100 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 101 set in CONFIG_LOCALVERSION.
228 102
229 (The actual string used here is the !! 103 (The actual string used here is the first eight characters produced
230 by running the command: 104 by running the command:
231 105
232 $ git rev-parse --verify HEAD 106 $ git rev-parse --verify HEAD
233 107
234 which is done within the script "scr 108 which is done within the script "scripts/setlocalversion".)
235 109
236 config BUILD_SALT <<
237 string "Build ID Salt" <<
238 default "" <<
239 help <<
240 The build ID is used to link binarie <<
241 this option will use the value in th <<
242 This is mostly useful for distributi <<
243 build is unique between builds. It's <<
244 <<
245 config HAVE_KERNEL_GZIP 110 config HAVE_KERNEL_GZIP
246 bool 111 bool
247 112
248 config HAVE_KERNEL_BZIP2 113 config HAVE_KERNEL_BZIP2
249 bool 114 bool
250 115
251 config HAVE_KERNEL_LZMA 116 config HAVE_KERNEL_LZMA
252 bool 117 bool
253 118
254 config HAVE_KERNEL_XZ 119 config HAVE_KERNEL_XZ
255 bool 120 bool
256 121
257 config HAVE_KERNEL_LZO 122 config HAVE_KERNEL_LZO
258 bool 123 bool
259 124
260 config HAVE_KERNEL_LZ4 125 config HAVE_KERNEL_LZ4
261 bool 126 bool
262 127
263 config HAVE_KERNEL_ZSTD <<
264 bool <<
265 <<
266 config HAVE_KERNEL_UNCOMPRESSED <<
267 bool <<
268 <<
269 choice 128 choice
270 prompt "Kernel compression mode" 129 prompt "Kernel compression mode"
271 default KERNEL_GZIP 130 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE !! 131 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
273 help 132 help
274 The linux kernel is a kind of self-e 133 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 134 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 135 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 136 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 137 Decompression speed is relevant at each boot.
279 138
280 If you have any problems with bzip2 139 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 140 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 141 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 142 supplied by Christian Ludwig)
284 143
285 High compression options are mostly 144 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 145 are low on disk space (embedded systems), but for whom ram
287 size matters less. 146 size matters less.
288 147
289 If in doubt, select 'gzip' 148 If in doubt, select 'gzip'
290 149
291 config KERNEL_GZIP 150 config KERNEL_GZIP
292 bool "Gzip" 151 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 152 depends on HAVE_KERNEL_GZIP
294 help 153 help
295 The old and tried gzip compression. 154 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 155 between compression ratio and decompression speed.
297 156
298 config KERNEL_BZIP2 157 config KERNEL_BZIP2
299 bool "Bzip2" 158 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 159 depends on HAVE_KERNEL_BZIP2
301 help 160 help
302 Its compression ratio and speed is i 161 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 162 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 163 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 164 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 165 will need at least 8MB RAM or more for booting.
307 166
308 config KERNEL_LZMA 167 config KERNEL_LZMA
309 bool "LZMA" 168 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 169 depends on HAVE_KERNEL_LZMA
311 help 170 help
312 This compression algorithm's ratio i 171 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 172 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 173 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 174
316 config KERNEL_XZ 175 config KERNEL_XZ
317 bool "XZ" 176 bool "XZ"
318 depends on HAVE_KERNEL_XZ 177 depends on HAVE_KERNEL_XZ
319 help 178 help
320 XZ uses the LZMA2 algorithm and inst 179 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 180 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 181 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 182 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 183 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 184 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 185
328 The speed is about the same as with 186 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 187 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 188 and LZO. Compression is slow.
331 189
332 config KERNEL_LZO 190 config KERNEL_LZO
333 bool "LZO" 191 bool "LZO"
334 depends on HAVE_KERNEL_LZO 192 depends on HAVE_KERNEL_LZO
335 help 193 help
336 Its compression ratio is the poorest 194 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 195 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 196 (both compression and decompression) is the fastest.
339 197
340 config KERNEL_LZ4 198 config KERNEL_LZ4
341 bool "LZ4" 199 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 200 depends on HAVE_KERNEL_LZ4
343 help 201 help
344 LZ4 is an LZ77-type compressor with 202 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 203 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 204 <https://code.google.com/p/lz4/>.
347 205
348 Its compression ratio is worse than 206 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 207 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 208 faster than LZO.
351 209
352 config KERNEL_ZSTD <<
353 bool "ZSTD" <<
354 depends on HAVE_KERNEL_ZSTD <<
355 help <<
356 ZSTD is a compression algorithm targ <<
357 with fast decompression speed. It wi <<
358 decompress around the same speed as <<
359 will need at least 192 KB RAM or mor <<
360 line tool is required for compressio <<
361 <<
362 config KERNEL_UNCOMPRESSED <<
363 bool "None" <<
364 depends on HAVE_KERNEL_UNCOMPRESSED <<
365 help <<
366 Produce uncompressed kernel image. T <<
367 you want. It is useful for debugging <<
368 environments, where decompressing an <<
369 slow. This option allows early boot <<
370 and jump right at uncompressed kerne <<
371 <<
372 endchoice 210 endchoice
373 211
374 config DEFAULT_INIT <<
375 string "Default init path" <<
376 default "" <<
377 help <<
378 This option determines the default i <<
379 option is passed on the kernel comma <<
380 not present, we will still then move <<
381 locations (e.g. /sbin/init, etc). If <<
382 the fallback list when init= is not <<
383 <<
384 config DEFAULT_HOSTNAME 212 config DEFAULT_HOSTNAME
385 string "Default hostname" 213 string "Default hostname"
386 default "(none)" 214 default "(none)"
387 help 215 help
388 This option determines the default s 216 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 217 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 218 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 219 system more usable with less configuration.
392 220
>> 221 config SWAP
>> 222 bool "Support for paging of anonymous memory (swap)"
>> 223 depends on MMU && BLOCK
>> 224 default y
>> 225 help
>> 226 This option allows you to choose whether you want to have support
>> 227 for so called swap devices or swap files in your kernel that are
>> 228 used to provide more virtual memory than the actual RAM present
>> 229 in your computer. If unsure say Y.
>> 230
393 config SYSVIPC 231 config SYSVIPC
394 bool "System V IPC" 232 bool "System V IPC"
395 help !! 233 ---help---
396 Inter Process Communication is a sui 234 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 235 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 236 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 237 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 238 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 239 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 240 you'll need to say Y here.
403 241
404 You can find documentation about IPC 242 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 243 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 244 <http://www.tldp.org/guides.html>.
407 245
408 config SYSVIPC_SYSCTL 246 config SYSVIPC_SYSCTL
409 bool 247 bool
410 depends on SYSVIPC 248 depends on SYSVIPC
411 depends on SYSCTL 249 depends on SYSCTL
412 default y 250 default y
413 251
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 252 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 253 bool "POSIX Message Queues"
420 depends on NET 254 depends on NET
421 help !! 255 ---help---
422 POSIX variant of message queues is a 256 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 257 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 258 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 259 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 260 queues (functions mq_*) say Y here.
427 261
428 POSIX message queues are visible as 262 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 263 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 264 operations on message queues.
431 265
432 If unsure, say Y. 266 If unsure, say Y.
433 267
434 config POSIX_MQUEUE_SYSCTL 268 config POSIX_MQUEUE_SYSCTL
435 bool 269 bool
436 depends on POSIX_MQUEUE 270 depends on POSIX_MQUEUE
437 depends on SYSCTL 271 depends on SYSCTL
438 default y 272 default y
439 273
440 config WATCH_QUEUE <<
441 bool "General notification queue" <<
442 default n <<
443 help <<
444 <<
445 This is a general notification queue <<
446 userspace by splicing them into pipe <<
447 with watches for key/keyring change <<
448 notifications. <<
449 <<
450 See Documentation/core-api/watch_que <<
451 <<
452 config CROSS_MEMORY_ATTACH 274 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 275 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 276 depends on MMU
455 default y 277 default y
456 help 278 help
457 Enabling this option adds the system 279 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 280 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 281 to directly read from or write to another process' address space.
460 See the man page for more details. 282 See the man page for more details.
461 283
>> 284 config FHANDLE
>> 285 bool "open by fhandle syscalls"
>> 286 select EXPORTFS
>> 287 help
>> 288 If you say Y here, a user level program will be able to map
>> 289 file names to handle and then later use the handle for
>> 290 different file system operations. This is useful in implementing
>> 291 userspace file servers, which now track files using handles instead
>> 292 of names. The handle would remain the same even if file names
>> 293 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
>> 294 syscalls.
>> 295
462 config USELIB 296 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 297 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 298 default y
465 help 299 help
466 This option enables the uselib sysca 300 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 301 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 302 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 303 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 304 running glibc can safely disable this.
471 305
472 config AUDIT 306 config AUDIT
473 bool "Auditing support" 307 bool "Auditing support"
474 depends on NET 308 depends on NET
475 help 309 help
476 Enable auditing infrastructure that 310 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 311 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy !! 312 logging of avc messages output). Does not do system-call
479 on architectures which support it. !! 313 auditing without CONFIG_AUDITSYSCALL.
480 314
481 config HAVE_ARCH_AUDITSYSCALL 315 config HAVE_ARCH_AUDITSYSCALL
482 bool 316 bool
483 317
484 config AUDITSYSCALL 318 config AUDITSYSCALL
485 def_bool y !! 319 bool "Enable system-call auditing support"
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 320 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
>> 321 default y if SECURITY_SELINUX
>> 322 help
>> 323 Enable low-overhead system-call auditing infrastructure that
>> 324 can be used independently or with another kernel subsystem,
>> 325 such as SELinux.
>> 326
>> 327 config AUDIT_WATCH
>> 328 def_bool y
>> 329 depends on AUDITSYSCALL
>> 330 select FSNOTIFY
>> 331
>> 332 config AUDIT_TREE
>> 333 def_bool y
>> 334 depends on AUDITSYSCALL
487 select FSNOTIFY 335 select FSNOTIFY
488 336
489 source "kernel/irq/Kconfig" 337 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 338 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" <<
492 source "kernel/Kconfig.preempt" <<
493 339
494 menu "CPU/Task time and stats accounting" 340 menu "CPU/Task time and stats accounting"
495 341
496 config VIRT_CPU_ACCOUNTING 342 config VIRT_CPU_ACCOUNTING
497 bool 343 bool
498 344
499 choice 345 choice
500 prompt "Cputime accounting" 346 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 347 default TICK_CPU_ACCOUNTING if !PPC64
>> 348 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 349
503 # Kind of a stub config for the pure tick base 350 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 351 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 352 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 353 depends on !S390 && !NO_HZ_FULL
507 help 354 help
508 This is the basic tick based cputime 355 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 356 statistics about user, system and idle time spent on per jiffies
510 granularity. 357 granularity.
511 358
512 If unsure, say Y. 359 If unsure, say Y.
513 360
514 config VIRT_CPU_ACCOUNTING_NATIVE 361 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 362 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 363 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 364 select VIRT_CPU_ACCOUNTING
518 help 365 help
519 Select this option to enable more ac 366 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 367 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 368 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 369 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 370 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 371 this also enables accounting of stolen time on logically-partitioned
525 systems. 372 systems.
526 373
527 config VIRT_CPU_ACCOUNTING_GEN 374 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 375 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 376 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 377 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS <<
532 select VIRT_CPU_ACCOUNTING 378 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 379 select CONTEXT_TRACKING
534 help 380 help
535 Select this option to enable task an 381 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 382 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 383 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 384 The accounting is thus performed at the expense of some significant
539 overhead. 385 overhead.
540 386
541 For now this is only useful if you a 387 For now this is only useful if you are working on the full
542 dynticks subsystem development. 388 dynticks subsystem development.
543 389
544 If unsure, say N. 390 If unsure, say N.
545 391
546 endchoice <<
547 <<
548 config IRQ_TIME_ACCOUNTING 392 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 393 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && !! 394 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
551 help 395 help
552 Select this option to enable fine gr 396 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 397 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 398 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 399 small performance impact.
556 400
557 If in doubt, say N here. 401 If in doubt, say N here.
558 402
559 config HAVE_SCHED_AVG_IRQ !! 403 endchoice
560 def_bool y <<
561 depends on IRQ_TIME_ACCOUNTING || PARA <<
562 depends on SMP <<
563 <<
564 config SCHED_HW_PRESSURE <<
565 bool <<
566 default y if ARM && ARM_CPU_TOPOLOGY <<
567 default y if ARM64 <<
568 depends on SMP <<
569 depends on CPU_FREQ_THERMAL <<
570 help <<
571 Select this option to enable HW pres <<
572 scheduler. HW pressure is the value <<
573 that reflects the reduction in CPU c <<
574 HW throttling. HW throttling occurs <<
575 a CPU is capped due to high operatin <<
576 <<
577 If selected, the scheduler will be a <<
578 i.e. put less load on throttled CPUs <<
579 <<
580 This requires the architecture to im <<
581 arch_update_hw_pressure() and arch_s <<
582 404
583 config BSD_PROCESS_ACCT 405 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 406 bool "BSD Process Accounting"
585 depends on MULTIUSER 407 depends on MULTIUSER
586 help 408 help
587 If you say Y here, a user level prog 409 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 410 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 411 information to a file: whenever a process exits, information about
590 that process will be appended to the 412 that process will be appended to the file by the kernel. The
591 information includes things such as 413 information includes things such as creation time, owning user,
592 command name, memory usage, controll 414 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 415 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 416 up to the user level program to do useful things with this
595 information. This is generally a go 417 information. This is generally a good idea, so say Y.
596 418
597 config BSD_PROCESS_ACCT_V3 419 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 420 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 421 depends on BSD_PROCESS_ACCT
600 default n 422 default n
601 help 423 help
602 If you say Y here, the process accou 424 If you say Y here, the process accounting information is written
603 in a new file format that also logs 425 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th !! 426 process and it's parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 427 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 428 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 429 at <http://www.gnu.org/software/acct/>.
608 430
609 config TASKSTATS 431 config TASKSTATS
610 bool "Export task/process statistics t 432 bool "Export task/process statistics through netlink"
611 depends on NET 433 depends on NET
612 depends on MULTIUSER 434 depends on MULTIUSER
613 default n 435 default n
614 help 436 help
615 Export selected statistics for tasks 437 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 438 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 439 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 440 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 441 space on task exit.
620 442
621 Say N if unsure. 443 Say N if unsure.
622 444
623 config TASK_DELAY_ACCT 445 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 446 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 447 depends on TASKSTATS
626 select SCHED_INFO 448 select SCHED_INFO
627 help 449 help
628 Collect information on time spent by 450 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 451 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 452 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 453 relative to other tasks for cpu, io, rss limits etc.
632 454
633 Say N if unsure. 455 Say N if unsure.
634 456
635 config TASK_XACCT 457 config TASK_XACCT
636 bool "Enable extended accounting over 458 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 459 depends on TASKSTATS
638 help 460 help
639 Collect extended task accounting dat 461 Collect extended task accounting data and send the data
640 to userland for processing over the 462 to userland for processing over the taskstats interface.
641 463
642 Say N if unsure. 464 Say N if unsure.
643 465
644 config TASK_IO_ACCOUNTING 466 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 467 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 468 depends on TASK_XACCT
647 help 469 help
648 Collect information on the number of 470 Collect information on the number of bytes of storage I/O which this
649 task has caused. 471 task has caused.
650 472
651 Say N if unsure. 473 Say N if unsure.
652 474
653 config PSI !! 475 endmenu # "CPU/Task time and stats accounting"
654 bool "Pressure stall information track !! 476
655 select KERNFS !! 477 menu "RCU Subsystem"
>> 478
>> 479 config TREE_RCU
>> 480 bool
>> 481 default y if !PREEMPT && SMP
656 help 482 help
657 Collect metrics that indicate how ov !! 483 This option selects the RCU implementation that is
658 and IO capacity are in the system. !! 484 designed for very large SMP system with hundreds or
>> 485 thousands of CPUs. It also scales down nicely to
>> 486 smaller systems.
659 487
660 If you say Y here, the kernel will c !! 488 config PREEMPT_RCU
661 pressure statistics files cpu, memor !! 489 bool
662 the share of walltime in which some !! 490 default y if PREEMPT
663 delayed due to contention of the res !! 491 help
664 !! 492 This option selects the RCU implementation that is
665 In kernels with cgroup support, cgro !! 493 designed for very large SMP systems with hundreds or
666 have cpu.pressure, memory.pressure, !! 494 thousands of CPUs, but for which real-time response
667 which aggregate pressure stalls for !! 495 is also required. It also scales down nicely to
>> 496 smaller systems.
668 497
669 For more details see Documentation/a !! 498 Select this option if you are unsure.
670 499
671 Say N if unsure. !! 500 config TINY_RCU
>> 501 bool
>> 502 default y if !PREEMPT && !SMP
>> 503 help
>> 504 This option selects the RCU implementation that is
>> 505 designed for UP systems from which real-time response
>> 506 is not required. This option greatly reduces the
>> 507 memory footprint of RCU.
672 508
673 config PSI_DEFAULT_DISABLED !! 509 config RCU_EXPERT
674 bool "Require boot parameter to enable !! 510 bool "Make expert-level adjustments to RCU configuration"
675 default n 511 default n
676 depends on PSI <<
677 help 512 help
678 If set, pressure stall information t !! 513 This option needs to be enabled if you wish to make
679 per default but can be enabled throu !! 514 expert-level adjustments to RCU configuration. By default,
680 kernel commandline during boot. !! 515 no such adjustments can be made, which has the often-beneficial
681 !! 516 side-effect of preventing "make oldconfig" from asking you all
682 This feature adds some code to the t !! 517 sorts of detailed questions about how you would like numerous
683 paths of the scheduler. The overhead !! 518 obscure RCU options to be set up.
684 common scheduling-intense workloads <<
685 webservers, memcache), but it does s <<
686 scheduler stress tests, such as hack <<
687 519
688 If you are paranoid and not sure wha !! 520 Say Y if you need to make expert-level adjustments to RCU.
689 used for, say Y. <<
690 521
691 Say N if unsure. !! 522 Say N if you are unsure.
692 523
693 endmenu # "CPU/Task time and stats accounting" !! 524 config SRCU
>> 525 bool
>> 526 help
>> 527 This option selects the sleepable version of RCU. This version
>> 528 permits arbitrary sleeping or blocking within RCU read-side critical
>> 529 sections.
694 530
695 config CPU_ISOLATION !! 531 config TASKS_RCU
696 bool "CPU isolation" !! 532 bool
697 depends on SMP || COMPILE_TEST !! 533 default n
698 default y !! 534 select SRCU
>> 535 help
>> 536 This option enables a task-based RCU implementation that uses
>> 537 only voluntary context switch (not preemption!), idle, and
>> 538 user-mode execution as quiescent states.
>> 539
>> 540 config RCU_STALL_COMMON
>> 541 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
>> 542 help
>> 543 This option enables RCU CPU stall code that is common between
>> 544 the TINY and TREE variants of RCU. The purpose is to allow
>> 545 the tiny variants to disable RCU CPU stall warnings, while
>> 546 making these warnings mandatory for the tree variants.
>> 547
>> 548 config CONTEXT_TRACKING
>> 549 bool
>> 550
>> 551 config CONTEXT_TRACKING_FORCE
>> 552 bool "Force context tracking"
>> 553 depends on CONTEXT_TRACKING
>> 554 default y if !NO_HZ_FULL
>> 555 help
>> 556 The major pre-requirement for full dynticks to work is to
>> 557 support the context tracking subsystem. But there are also
>> 558 other dependencies to provide in order to make the full
>> 559 dynticks working.
>> 560
>> 561 This option stands for testing when an arch implements the
>> 562 context tracking backend but doesn't yet fullfill all the
>> 563 requirements to make the full dynticks feature working.
>> 564 Without the full dynticks, there is no way to test the support
>> 565 for context tracking and the subsystems that rely on it: RCU
>> 566 userspace extended quiescent state and tickless cputime
>> 567 accounting. This option copes with the absence of the full
>> 568 dynticks subsystem by forcing the context tracking on all
>> 569 CPUs in the system.
>> 570
>> 571 Say Y only if you're working on the development of an
>> 572 architecture backend for the context tracking.
>> 573
>> 574 Say N otherwise, this option brings an overhead that you
>> 575 don't want in production.
>> 576
>> 577
>> 578 config RCU_FANOUT
>> 579 int "Tree-based hierarchical RCU fanout value"
>> 580 range 2 64 if 64BIT
>> 581 range 2 32 if !64BIT
>> 582 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
>> 583 default 64 if 64BIT
>> 584 default 32 if !64BIT
>> 585 help
>> 586 This option controls the fanout of hierarchical implementations
>> 587 of RCU, allowing RCU to work efficiently on machines with
>> 588 large numbers of CPUs. This value must be at least the fourth
>> 589 root of NR_CPUS, which allows NR_CPUS to be insanely large.
>> 590 The default value of RCU_FANOUT should be used for production
>> 591 systems, but if you are stress-testing the RCU implementation
>> 592 itself, small RCU_FANOUT values allow you to test large-system
>> 593 code paths on small(er) systems.
>> 594
>> 595 Select a specific number if testing RCU itself.
>> 596 Take the default if unsure.
>> 597
>> 598 config RCU_FANOUT_LEAF
>> 599 int "Tree-based hierarchical RCU leaf-level fanout value"
>> 600 range 2 64 if 64BIT
>> 601 range 2 32 if !64BIT
>> 602 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
>> 603 default 16
>> 604 help
>> 605 This option controls the leaf-level fanout of hierarchical
>> 606 implementations of RCU, and allows trading off cache misses
>> 607 against lock contention. Systems that synchronize their
>> 608 scheduling-clock interrupts for energy-efficiency reasons will
>> 609 want the default because the smaller leaf-level fanout keeps
>> 610 lock contention levels acceptably low. Very large systems
>> 611 (hundreds or thousands of CPUs) will instead want to set this
>> 612 value to the maximum value possible in order to reduce the
>> 613 number of cache misses incurred during RCU's grace-period
>> 614 initialization. These systems tend to run CPU-bound, and thus
>> 615 are not helped by synchronized interrupts, and thus tend to
>> 616 skew them, which reduces lock contention enough that large
>> 617 leaf-level fanouts work well.
>> 618
>> 619 Select a specific number if testing RCU itself.
>> 620
>> 621 Select the maximum permissible value for large systems.
>> 622
>> 623 Take the default if unsure.
>> 624
>> 625 config RCU_FAST_NO_HZ
>> 626 bool "Accelerate last non-dyntick-idle CPU's grace periods"
>> 627 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
>> 628 default n
>> 629 help
>> 630 This option permits CPUs to enter dynticks-idle state even if
>> 631 they have RCU callbacks queued, and prevents RCU from waking
>> 632 these CPUs up more than roughly once every four jiffies (by
>> 633 default, you can adjust this using the rcutree.rcu_idle_gp_delay
>> 634 parameter), thus improving energy efficiency. On the other
>> 635 hand, this option increases the duration of RCU grace periods,
>> 636 for example, slowing down synchronize_rcu().
>> 637
>> 638 Say Y if energy efficiency is critically important, and you
>> 639 don't care about increased grace-period durations.
>> 640
>> 641 Say N if you are unsure.
>> 642
>> 643 config TREE_RCU_TRACE
>> 644 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
>> 645 select DEBUG_FS
>> 646 help
>> 647 This option provides tracing for the TREE_RCU and
>> 648 PREEMPT_RCU implementations, permitting Makefile to
>> 649 trivially select kernel/rcutree_trace.c.
>> 650
>> 651 config RCU_BOOST
>> 652 bool "Enable RCU priority boosting"
>> 653 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
>> 654 default n
699 help 655 help
700 Make sure that CPUs running critical !! 656 This option boosts the priority of preempted RCU readers that
701 any source of "noise" such as unboun !! 657 block the current preemptible RCU grace period for too long.
702 Unbound jobs get offloaded to housek !! 658 This option also prevents heavy loads from blocking RCU
703 the "isolcpus=" boot parameter. !! 659 callback invocation for all flavors of RCU.
>> 660
>> 661 Say Y here if you are working with real-time apps or heavy loads
>> 662 Say N here if you are unsure.
>> 663
>> 664 config RCU_KTHREAD_PRIO
>> 665 int "Real-time priority to use for RCU worker threads"
>> 666 range 1 99 if RCU_BOOST
>> 667 range 0 99 if !RCU_BOOST
>> 668 default 1 if RCU_BOOST
>> 669 default 0 if !RCU_BOOST
>> 670 depends on RCU_EXPERT
>> 671 help
>> 672 This option specifies the SCHED_FIFO priority value that will be
>> 673 assigned to the rcuc/n and rcub/n threads and is also the value
>> 674 used for RCU_BOOST (if enabled). If you are working with a
>> 675 real-time application that has one or more CPU-bound threads
>> 676 running at a real-time priority level, you should set
>> 677 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
>> 678 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
>> 679 value of 1 is appropriate in the common case, which is real-time
>> 680 applications that do not have any CPU-bound threads.
>> 681
>> 682 Some real-time applications might not have a single real-time
>> 683 thread that saturates a given CPU, but instead might have
>> 684 multiple real-time threads that, taken together, fully utilize
>> 685 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
>> 686 a priority higher than the lowest-priority thread that is
>> 687 conspiring to prevent the CPU from running any non-real-time
>> 688 tasks. For example, if one thread at priority 10 and another
>> 689 thread at priority 5 are between themselves fully consuming
>> 690 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
>> 691 set to priority 6 or higher.
>> 692
>> 693 Specify the real-time priority, or take the default if unsure.
>> 694
>> 695 config RCU_BOOST_DELAY
>> 696 int "Milliseconds to delay boosting after RCU grace-period start"
>> 697 range 0 3000
>> 698 depends on RCU_BOOST
>> 699 default 500
>> 700 help
>> 701 This option specifies the time to wait after the beginning of
>> 702 a given grace period before priority-boosting preempted RCU
>> 703 readers blocking that grace period. Note that any RCU reader
>> 704 blocking an expedited RCU grace period is boosted immediately.
>> 705
>> 706 Accept the default if unsure.
>> 707
>> 708 config RCU_NOCB_CPU
>> 709 bool "Offload RCU callback processing from boot-selected CPUs"
>> 710 depends on TREE_RCU || PREEMPT_RCU
>> 711 depends on RCU_EXPERT || NO_HZ_FULL
>> 712 default n
>> 713 help
>> 714 Use this option to reduce OS jitter for aggressive HPC or
>> 715 real-time workloads. It can also be used to offload RCU
>> 716 callback invocation to energy-efficient CPUs in battery-powered
>> 717 asymmetric multiprocessors.
>> 718
>> 719 This option offloads callback invocation from the set of
>> 720 CPUs specified at boot time by the rcu_nocbs parameter.
>> 721 For each such CPU, a kthread ("rcuox/N") will be created to
>> 722 invoke callbacks, where the "N" is the CPU being offloaded,
>> 723 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
>> 724 "s" for RCU-sched. Nothing prevents this kthread from running
>> 725 on the specified CPUs, but (1) the kthreads may be preempted
>> 726 between each callback, and (2) affinity or cgroups can be used
>> 727 to force the kthreads to run on whatever set of CPUs is desired.
704 728
705 Say Y if unsure. !! 729 Say Y here if you want to help to debug reduced OS jitter.
>> 730 Say N here if you are unsure.
>> 731
>> 732 choice
>> 733 prompt "Build-forced no-CBs CPUs"
>> 734 default RCU_NOCB_CPU_NONE
>> 735 depends on RCU_NOCB_CPU
>> 736 help
>> 737 This option allows no-CBs CPUs (whose RCU callbacks are invoked
>> 738 from kthreads rather than from softirq context) to be specified
>> 739 at build time. Additional no-CBs CPUs may be specified by
>> 740 the rcu_nocbs= boot parameter.
>> 741
>> 742 config RCU_NOCB_CPU_NONE
>> 743 bool "No build_forced no-CBs CPUs"
>> 744 help
>> 745 This option does not force any of the CPUs to be no-CBs CPUs.
>> 746 Only CPUs designated by the rcu_nocbs= boot parameter will be
>> 747 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
>> 748 kthreads whose names begin with "rcuo". All other CPUs will
>> 749 invoke their own RCU callbacks in softirq context.
>> 750
>> 751 Select this option if you want to choose no-CBs CPUs at
>> 752 boot time, for example, to allow testing of different no-CBs
>> 753 configurations without having to rebuild the kernel each time.
>> 754
>> 755 config RCU_NOCB_CPU_ZERO
>> 756 bool "CPU 0 is a build_forced no-CBs CPU"
>> 757 help
>> 758 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
>> 759 callbacks are invoked by a per-CPU kthread whose name begins
>> 760 with "rcuo". Additional CPUs may be designated as no-CBs
>> 761 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
>> 762 All other CPUs will invoke their own RCU callbacks in softirq
>> 763 context.
>> 764
>> 765 Select this if CPU 0 needs to be a no-CBs CPU for real-time
>> 766 or energy-efficiency reasons, but the real reason it exists
>> 767 is to ensure that randconfig testing covers mixed systems.
>> 768
>> 769 config RCU_NOCB_CPU_ALL
>> 770 bool "All CPUs are build_forced no-CBs CPUs"
>> 771 help
>> 772 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
>> 773 boot parameter will be ignored. All CPUs' RCU callbacks will
>> 774 be executed in the context of per-CPU rcuo kthreads created for
>> 775 this purpose. Assuming that the kthreads whose names start with
>> 776 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
>> 777 on the remaining CPUs, but might decrease memory locality during
>> 778 RCU-callback invocation, thus potentially degrading throughput.
>> 779
>> 780 Select this if all CPUs need to be no-CBs CPUs for real-time
>> 781 or energy-efficiency reasons.
>> 782
>> 783 endchoice
>> 784
>> 785 config RCU_EXPEDITE_BOOT
>> 786 bool
>> 787 default n
>> 788 help
>> 789 This option enables expedited grace periods at boot time,
>> 790 as if rcu_expedite_gp() had been invoked early in boot.
>> 791 The corresponding rcu_unexpedite_gp() is invoked from
>> 792 rcu_end_inkernel_boot(), which is intended to be invoked
>> 793 at the end of the kernel-only boot sequence, just before
>> 794 init is exec'ed.
>> 795
>> 796 Accept the default if unsure.
>> 797
>> 798 endmenu # "RCU Subsystem"
706 799
707 source "kernel/rcu/Kconfig" !! 800 config BUILD_BIN2C
>> 801 bool
>> 802 default n
708 803
709 config IKCONFIG 804 config IKCONFIG
710 tristate "Kernel .config support" 805 tristate "Kernel .config support"
711 help !! 806 select BUILD_BIN2C
>> 807 ---help---
712 This option enables the complete Lin 808 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 809 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 810 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 811 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 812 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 813 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 814 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 815 /proc/config.gz if enabled (below).
720 816
721 config IKCONFIG_PROC 817 config IKCONFIG_PROC
722 bool "Enable access to .config through 818 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 819 depends on IKCONFIG && PROC_FS
724 help !! 820 ---help---
725 This option enables access to the ke 821 This option enables access to the kernel configuration file
726 through /proc/config.gz. 822 through /proc/config.gz.
727 823
728 config IKHEADERS <<
729 tristate "Enable kernel headers throug <<
730 depends on SYSFS <<
731 help <<
732 This option enables access to the in <<
733 the build process. These can be used <<
734 or similar programs. If you build t <<
735 kheaders.ko is built which can be lo <<
736 <<
737 config LOG_BUF_SHIFT 824 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 825 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 826 range 12 25 if !H8300
>> 827 range 12 19 if H8300
740 default 17 828 default 17
741 depends on PRINTK 829 depends on PRINTK
742 help 830 help
743 Select the minimal kernel log buffer 831 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 832 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 833 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 834 by "log_buf_len" boot parameter.
747 835
748 Examples: 836 Examples:
749 17 => 128 KB 837 17 => 128 KB
750 16 => 64 KB 838 16 => 64 KB
751 15 => 32 KB 839 15 => 32 KB
752 14 => 16 KB 840 14 => 16 KB
753 13 => 8 KB 841 13 => 8 KB
754 12 => 4 KB 842 12 => 4 KB
755 843
756 config LOG_CPU_MAX_BUF_SHIFT 844 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 845 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 846 depends on SMP
759 range 0 21 847 range 0 21
>> 848 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 849 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 850 depends on PRINTK
763 help 851 help
764 This option allows to increase the d 852 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 853 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 854 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 855 lines however it might be much more when problems are reported,
768 e.g. backtraces. 856 e.g. backtraces.
769 857
770 The increased size means that a new 858 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 859 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 860 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 861 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 862 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed !! 863 so that more than 64 CPUs are needed to trigger the allocation.
776 864
777 Also this option is ignored when "lo 865 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 866 used as it forces an exact (power of two) size of the ring buffer.
779 867
780 The number of possible CPUs is used 868 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o !! 869 hotplugging making the compuation optimal for the the worst case
782 scenario while allowing a simple alg !! 870 scenerio while allowing a simple algorithm to be used from bootup.
783 871
784 Examples shift values and their mean 872 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 873 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 874 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 875 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 876 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 877 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 878 12 => 4 KB for each CPU
791 879
792 config PRINTK_INDEX <<
793 bool "Printk indexing debugfs interfac <<
794 depends on PRINTK && DEBUG_FS <<
795 help <<
796 Add support for indexing of all prin <<
797 at <debugfs>/printk/index/<module>. <<
798 <<
799 This can be used as part of maintain <<
800 /dev/kmsg, as it permits auditing th <<
801 kernel, allowing detection of cases <<
802 changed or no longer present. <<
803 <<
804 There is no additional runtime cost <<
805 <<
806 # 880 #
807 # Architectures with an unreliable sched_clock 881 # Architectures with an unreliable sched_clock() should select this:
808 # 882 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 883 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 884 bool
811 885
812 config GENERIC_SCHED_CLOCK 886 config GENERIC_SCHED_CLOCK
813 bool 887 bool
814 888
815 menu "Scheduler features" <<
816 <<
817 config UCLAMP_TASK <<
818 bool "Enable utilization clamping for <<
819 depends on CPU_FREQ_GOV_SCHEDUTIL <<
820 help <<
821 This feature enables the scheduler t <<
822 of each CPU based on RUNNABLE tasks <<
823 <<
824 With this option, the user can speci <<
825 utilization allowed for RUNNABLE tas <<
826 the maximum frequency a task should <<
827 defines the minimum frequency it sho <<
828 <<
829 Both min and max utilization clamp v <<
830 aiming at improving its frequency se <<
831 enforce or grant any specific bandwi <<
832 <<
833 If in doubt, say N. <<
834 <<
835 config UCLAMP_BUCKETS_COUNT <<
836 int "Number of supported utilization c <<
837 range 5 20 <<
838 default 5 <<
839 depends on UCLAMP_TASK <<
840 help <<
841 Defines the number of clamp buckets <<
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ <<
843 number of clamp buckets the finer th <<
844 the precision of clamping aggregatio <<
845 <<
846 For example, with the minimum config <<
847 clamp buckets tracking 20% utilizati <<
848 be refcounted in the [20..39]% bucke <<
849 effective value to 25%. <<
850 If a second 30% boosted task should <<
851 that task will be refcounted in the <<
852 it will boost the bucket clamp effec <<
853 The clamp effective value of a bucke <<
854 (20% in the example above) when ther <<
855 that bucket. <<
856 <<
857 An additional boost/capping margin c <<
858 example above the 25% task will be b <<
859 CPU. If that should be considered no <<
860 it's always possible to reduce the m <<
861 clamp buckets to trade off used memo <<
862 precision. <<
863 <<
864 If in doubt, use the default value. <<
865 <<
866 endmenu <<
867 <<
868 # 889 #
869 # For architectures that want to enable the su 890 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 891 # balancing logic:
871 # 892 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 893 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 894 bool
874 895
875 # 896 #
876 # For architectures that prefer to flush all T 897 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 898 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 899 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 900 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 901 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 902 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 903 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 904 bool
884 905
885 config CC_HAS_INT128 <<
886 def_bool !$(cc-option,$(m64-flag) -D__ <<
887 <<
888 config CC_IMPLICIT_FALLTHROUGH <<
889 string <<
890 default "-Wimplicit-fallthrough=5" if <<
891 default "-Wimplicit-fallthrough" if CC <<
892 <<
893 # Currently, disable gcc-10+ array-bounds glob <<
894 # It's still broken in gcc-13, so no upper bou <<
895 config GCC10_NO_ARRAY_BOUNDS <<
896 def_bool y <<
897 <<
898 config CC_NO_ARRAY_BOUNDS <<
899 bool <<
900 default y if CC_IS_GCC && GCC_VERSION <<
901 <<
902 # Currently, disable -Wstringop-overflow for G <<
903 config GCC_NO_STRINGOP_OVERFLOW <<
904 def_bool y <<
905 <<
906 config CC_NO_STRINGOP_OVERFLOW <<
907 bool <<
908 default y if CC_IS_GCC && GCC_NO_STRIN <<
909 <<
910 config CC_STRINGOP_OVERFLOW <<
911 bool <<
912 default y if CC_IS_GCC && !CC_NO_STRIN <<
913 <<
914 # 906 #
915 # For architectures that know their GCC __int1 907 # For architectures that know their GCC __int128 support is sound
916 # 908 #
917 config ARCH_SUPPORTS_INT128 909 config ARCH_SUPPORTS_INT128
918 bool 910 bool
919 911
920 # For architectures that (ab)use NUMA to repre 912 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 913 # all cpu-local but of different latencies, such as SuperH.
922 # 914 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 915 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 916 bool
925 917
926 config NUMA_BALANCING 918 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 919 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 920 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 921 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 922 depends on SMP && NUMA && MIGRATION
931 help 923 help
932 This option adds support for automat 924 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 925 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 926 it has references to the node the task is running on.
935 927
936 This system will be inactive on UMA 928 This system will be inactive on UMA systems.
937 929
938 config NUMA_BALANCING_DEFAULT_ENABLED 930 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 931 bool "Automatically enable NUMA aware memory/task placement"
940 default y 932 default y
941 depends on NUMA_BALANCING 933 depends on NUMA_BALANCING
942 help 934 help
943 If set, automatic NUMA balancing wil 935 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 936 machine.
945 937
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 938 menuconfig CGROUPS
950 bool "Control Group support" 939 bool "Control Group support"
951 select KERNFS 940 select KERNFS
952 help 941 help
953 This option adds support for groupin 942 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 943 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 944 controls or device isolation.
956 See 945 See
957 - Documentation/scheduler/sche !! 946 - Documentation/scheduler/sched-design-CFS.txt (CFS)
958 - Documentation/admin-guide/cg !! 947 - Documentation/cgroups/ (features for grouping, isolation
959 and 948 and resource control)
960 949
961 Say N if unsure. 950 Say N if unsure.
962 951
963 if CGROUPS 952 if CGROUPS
964 953
965 config PAGE_COUNTER !! 954 config CGROUP_DEBUG
966 bool !! 955 bool "Example debug cgroup subsystem"
>> 956 default n
>> 957 help
>> 958 This option enables a simple cgroup subsystem that
>> 959 exports useful debugging information about the cgroups
>> 960 framework.
>> 961
>> 962 Say N if unsure.
>> 963
>> 964 config CGROUP_FREEZER
>> 965 bool "Freezer cgroup subsystem"
>> 966 help
>> 967 Provides a way to freeze and unfreeze all tasks in a
>> 968 cgroup.
>> 969
>> 970 config CGROUP_PIDS
>> 971 bool "PIDs cgroup subsystem"
>> 972 help
>> 973 Provides enforcement of process number limits in the scope of a
>> 974 cgroup. Any attempt to fork more processes than is allowed in the
>> 975 cgroup will fail. PIDs are fundamentally a global resource because it
>> 976 is fairly trivial to reach PID exhaustion before you reach even a
>> 977 conservative kmemcg limit. As a result, it is possible to grind a
>> 978 system to halt without being limited by other cgroup policies. The
>> 979 PIDs cgroup subsystem is designed to stop this from happening.
>> 980
>> 981 It should be noted that organisational operations (such as attaching
>> 982 to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
>> 983 since the PIDs limit only affects a process's ability to fork, not to
>> 984 attach to a cgroup.
967 985
968 config CGROUP_FAVOR_DYNMODS !! 986 config CGROUP_DEVICE
969 bool "Favor dynamic modification laten !! 987 bool "Device controller for cgroups"
970 help !! 988 help
971 This option enables the "favordynmod !! 989 Provides a cgroup implementing whitelists for devices which
972 which reduces the latencies of dynam !! 990 a process in the cgroup can mknod or open.
973 as task migrations and controller on !! 991
974 hot path operations such as forks an !! 992 config CPUSETS
>> 993 bool "Cpuset support"
>> 994 help
>> 995 This option will let you create and manage CPUSETs which
>> 996 allow dynamically partitioning a system into sets of CPUs and
>> 997 Memory Nodes and assigning tasks to run only within those sets.
>> 998 This is primarily useful on large SMP or NUMA systems.
>> 999
>> 1000 Say N if unsure.
>> 1001
>> 1002 config PROC_PID_CPUSET
>> 1003 bool "Include legacy /proc/<pid>/cpuset file"
>> 1004 depends on CPUSETS
>> 1005 default y
>> 1006
>> 1007 config CGROUP_CPUACCT
>> 1008 bool "Simple CPU accounting cgroup subsystem"
>> 1009 help
>> 1010 Provides a simple Resource Controller for monitoring the
>> 1011 total CPU consumed by the tasks in a cgroup.
975 1012
976 Say N if unsure. !! 1013 config PAGE_COUNTER
>> 1014 bool
977 1015
978 config MEMCG 1016 config MEMCG
979 bool "Memory controller" !! 1017 bool "Memory Resource Controller for Control Groups"
980 select PAGE_COUNTER 1018 select PAGE_COUNTER
981 select EVENTFD 1019 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 1020 help
984 Provides control over the memory foo !! 1021 Provides a memory resource controller that manages both anonymous
>> 1022 memory and page cache. (See Documentation/cgroups/memory.txt)
985 1023
986 config MEMCG_V1 !! 1024 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 1025 bool "Memory Resource Controller Swap Extension"
>> 1026 depends on MEMCG && SWAP
>> 1027 help
>> 1028 Add swap management feature to memory resource controller. When you
>> 1029 enable this, you can limit mem+swap usage per cgroup. In other words,
>> 1030 when you disable this, memory resource controller has no cares to
>> 1031 usage of swap...a process can exhaust all of the swap. This extension
>> 1032 is useful when you want to avoid exhaustion swap but this itself
>> 1033 adds more overheads and consumes memory for remembering information.
>> 1034 Especially if you use 32bit system or small memory system, please
>> 1035 be careful about enabling this. When memory resource controller
>> 1036 is disabled by boot option, this will be automatically disabled and
>> 1037 there will be no overhead from this. Even when you set this config=y,
>> 1038 if boot option "swapaccount=0" is set, swap will not be accounted.
>> 1039 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
>> 1040 size is 4096bytes, 512k per 1Gbytes of swap.
>> 1041 config MEMCG_SWAP_ENABLED
>> 1042 bool "Memory Resource Controller Swap Extension enabled by default"
>> 1043 depends on MEMCG_SWAP
>> 1044 default y
>> 1045 help
>> 1046 Memory Resource Controller Swap Extension comes with its price in
>> 1047 a bigger memory consumption. General purpose distribution kernels
>> 1048 which want to enable the feature but keep it disabled by default
>> 1049 and let the user enable it by swapaccount=1 boot command line
>> 1050 parameter should have this option unselected.
>> 1051 For those who want to have the feature enabled by default should
>> 1052 select this option (if, for some reason, they need to disable it
>> 1053 then swapaccount=0 does the trick).
>> 1054 config MEMCG_KMEM
>> 1055 bool "Memory Resource Controller Kernel Memory accounting"
988 depends on MEMCG 1056 depends on MEMCG
989 default n !! 1057 depends on SLUB || SLAB
990 help 1058 help
991 Legacy cgroup v1 memory controller w !! 1059 The Kernel Memory extension for Memory Resource Controller can limit
992 cgroup v2 implementation. The v1 is !! 1060 the amount of memory used by kernel objects in the system. Those are
993 which haven't migrated to the new cg !! 1061 fundamentally different from the entities handled by the standard
994 do not have any such application the !! 1062 Memory Controller, which are page-based, and can be swapped. Users of
995 this option disabled. !! 1063 the kmem extension can use it to guarantee that no group of processes
996 !! 1064 will ever exhaust kernel resources alone.
997 Please note that feature set of the <<
998 going to shrink due to deprecation p <<
999 controller are highly discouraged. <<
1000 <<
1001 Say N if unsure. <<
1002 1065
1003 config BLK_CGROUP !! 1066 config CGROUP_HUGETLB
1004 bool "IO controller" !! 1067 bool "HugeTLB Resource Controller for Control Groups"
1005 depends on BLOCK !! 1068 depends on HUGETLB_PAGE
>> 1069 select PAGE_COUNTER
1006 default n 1070 default n
1007 help 1071 help
1008 Generic block IO controller cgroup in !! 1072 Provides a cgroup Resource Controller for HugeTLB pages.
1009 cgroup interface which should be used !! 1073 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1010 policies. !! 1074 The limit is enforced during page fault. Since HugeTLB doesn't
1011 !! 1075 support page reclaim, enforcing the limit at page fault time implies
1012 Currently, CFQ IO scheduler uses it t !! 1076 that, the application will get SIGBUS signal if it tries to access
1013 control disk bandwidth allocation (pr !! 1077 HugeTLB pages beyond its limit. This requires the application to know
1014 to such task groups. It is also used !! 1078 beforehand how much HugeTLB pages it would require for its use. The
1015 block layer to implement upper limit !! 1079 control group is tracked in the third page lru pointer. This means
1016 !! 1080 that we cannot use the controller with huge page less than 3 pages.
1017 This option only enables generic Bloc <<
1018 One needs to also enable actual IO co <<
1019 enabling proportional weight division <<
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl <<
1021 CONFIG_BLK_DEV_THROTTLING=y. <<
1022 1081
1023 See Documentation/admin-guide/cgroup- !! 1082 config CGROUP_PERF
>> 1083 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
>> 1084 depends on PERF_EVENTS && CGROUPS
>> 1085 help
>> 1086 This option extends the per-cpu mode to restrict monitoring to
>> 1087 threads which belong to the cgroup specified and run on the
>> 1088 designated cpu.
1024 1089
1025 config CGROUP_WRITEBACK !! 1090 Say N if unsure.
1026 bool <<
1027 depends on MEMCG && BLK_CGROUP <<
1028 default y <<
1029 1091
1030 menuconfig CGROUP_SCHED 1092 menuconfig CGROUP_SCHED
1031 bool "CPU controller" !! 1093 bool "Group CPU scheduler"
1032 default n 1094 default n
1033 help 1095 help
1034 This feature lets CPU scheduler rec 1096 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 1097 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 1098 tasks.
1037 1099
1038 if CGROUP_SCHED 1100 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 1101 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 1102 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 1103 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 1104 default CGROUP_SCHED
1047 1105
1048 config CFS_BANDWIDTH 1106 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 1107 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 1108 depends on FAIR_GROUP_SCHED
1051 default n 1109 default n
1052 help 1110 help
1053 This option allows users to define 1111 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 1112 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 1113 set are considered to be unconstrained and will run with no
1056 restriction. 1114 restriction.
1057 See Documentation/scheduler/sched-b !! 1115 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1058 1116
1059 config RT_GROUP_SCHED 1117 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 1118 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 1119 depends on CGROUP_SCHED
1062 default n 1120 default n
1063 help 1121 help
1064 This feature lets you explicitly al 1122 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 1123 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 1124 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 1125 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r !! 1126 See Documentation/scheduler/sched-rt-group.txt for more information.
1069 <<
1070 config EXT_GROUP_SCHED <<
1071 bool <<
1072 depends on SCHED_CLASS_EXT && CGROUP_ <<
1073 select GROUP_SCHED_WEIGHT <<
1074 default y <<
1075 1127
1076 endif #CGROUP_SCHED 1128 endif #CGROUP_SCHED
1077 1129
1078 config SCHED_MM_CID !! 1130 config BLK_CGROUP
1079 def_bool y !! 1131 bool "Block IO controller"
1080 depends on SMP && RSEQ !! 1132 depends on BLOCK
1081 <<
1082 config UCLAMP_TASK_GROUP <<
1083 bool "Utilization clamping per group <<
1084 depends on CGROUP_SCHED <<
1085 depends on UCLAMP_TASK <<
1086 default n 1133 default n
1087 help !! 1134 ---help---
1088 This feature enables the scheduler !! 1135 Generic block IO controller cgroup interface. This is the common
1089 of each CPU based on RUNNABLE tasks !! 1136 cgroup interface which should be used by various IO controlling
1090 !! 1137 policies.
1091 When this option is enabled, the us <<
1092 CPU bandwidth which is allowed for <<
1093 The max bandwidth allows to clamp t <<
1094 can use, while the min bandwidth al <<
1095 frequency a task will always use. <<
1096 <<
1097 When task group based utilization c <<
1098 specified task-specific clamp value <<
1099 specified clamp value. Both minimum <<
1100 be bigger than the corresponding cl <<
1101 <<
1102 If in doubt, say N. <<
1103 <<
1104 config CGROUP_PIDS <<
1105 bool "PIDs controller" <<
1106 help <<
1107 Provides enforcement of process num <<
1108 cgroup. Any attempt to fork more pr <<
1109 cgroup will fail. PIDs are fundamen <<
1110 is fairly trivial to reach PID exha <<
1111 conservative kmemcg limit. As a res <<
1112 system to halt without being limite <<
1113 PIDs controller is designed to stop <<
1114 <<
1115 It should be noted that organisatio <<
1116 to a cgroup hierarchy) will *not* b <<
1117 since the PIDs limit only affects a <<
1118 attach to a cgroup. <<
1119 <<
1120 config CGROUP_RDMA <<
1121 bool "RDMA controller" <<
1122 help <<
1123 Provides enforcement of RDMA resour <<
1124 It is fairly easy for consumers to <<
1125 can result into resource unavailabi <<
1126 RDMA controller is designed to stop <<
1127 Attaching processes with active RDM <<
1128 hierarchy is allowed even if can cr <<
1129 <<
1130 config CGROUP_FREEZER <<
1131 bool "Freezer controller" <<
1132 help <<
1133 Provides a way to freeze and unfree <<
1134 cgroup. <<
1135 <<
1136 This option affects the ORIGINAL cg <<
1137 controller includes important in-ke <<
1138 <<
1139 If you're using cgroup2, say N. <<
1140 1138
1141 config CGROUP_HUGETLB !! 1139 Currently, CFQ IO scheduler uses it to recognize task groups and
1142 bool "HugeTLB controller" !! 1140 control disk bandwidth allocation (proportional time slice allocation)
1143 depends on HUGETLB_PAGE !! 1141 to such task groups. It is also used by bio throttling logic in
1144 select PAGE_COUNTER !! 1142 block layer to implement upper limit in IO rates on a device.
1145 default n <<
1146 help <<
1147 Provides a cgroup controller for Hu <<
1148 When you enable this, you can put a <<
1149 The limit is enforced during page f <<
1150 support page reclaim, enforcing the <<
1151 that, the application will get SIGB <<
1152 HugeTLB pages beyond its limit. Thi <<
1153 beforehand how much HugeTLB pages i <<
1154 control group is tracked in the thi <<
1155 that we cannot use the controller w <<
1156 1143
1157 config CPUSETS !! 1144 This option only enables generic Block IO controller infrastructure.
1158 bool "Cpuset controller" !! 1145 One needs to also enable actual IO controlling logic/policy. For
1159 depends on SMP !! 1146 enabling proportional weight division of disk bandwidth in CFQ, set
1160 help !! 1147 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1161 This option will let you create and !! 1148 CONFIG_BLK_DEV_THROTTLING=y.
1162 allow dynamically partitioning a sy <<
1163 Memory Nodes and assigning tasks to <<
1164 This is primarily useful on large S <<
1165 1149
1166 Say N if unsure. !! 1150 See Documentation/cgroups/blkio-controller.txt for more information.
1167 1151
1168 config CPUSETS_V1 !! 1152 config DEBUG_BLK_CGROUP
1169 bool "Legacy cgroup v1 cpusets contro !! 1153 bool "Enable Block IO controller debugging"
1170 depends on CPUSETS !! 1154 depends on BLK_CGROUP
1171 default n 1155 default n
1172 help !! 1156 ---help---
1173 Legacy cgroup v1 cpusets controller !! 1157 Enable some debugging help. Currently it exports additional stat
1174 cgroup v2 implementation. The v1 is !! 1158 files in a cgroup which can be useful for debugging.
1175 which haven't migrated to the new c <<
1176 do not have any such application th <<
1177 this option disabled. <<
1178 <<
1179 Say N if unsure. <<
1180 1159
1181 config PROC_PID_CPUSET !! 1160 config CGROUP_WRITEBACK
1182 bool "Include legacy /proc/<pid>/cpus !! 1161 bool
1183 depends on CPUSETS !! 1162 depends on MEMCG && BLK_CGROUP
1184 default y 1163 default y
1185 1164
1186 config CGROUP_DEVICE !! 1165 endif # CGROUPS
1187 bool "Device controller" <<
1188 help <<
1189 Provides a cgroup controller implem <<
1190 devices which a process in the cgro <<
1191 <<
1192 config CGROUP_CPUACCT <<
1193 bool "Simple CPU accounting controlle <<
1194 help <<
1195 Provides a simple controller for mo <<
1196 total CPU consumed by the tasks in <<
1197 <<
1198 config CGROUP_PERF <<
1199 bool "Perf controller" <<
1200 depends on PERF_EVENTS <<
1201 help <<
1202 This option extends the perf per-cp <<
1203 to threads which belong to the cgro <<
1204 designated cpu. Or this can be use <<
1205 so that it can monitor performance <<
1206 <<
1207 Say N if unsure. <<
1208 <<
1209 config CGROUP_BPF <<
1210 bool "Support for eBPF programs attac <<
1211 depends on BPF_SYSCALL <<
1212 select SOCK_CGROUP_DATA <<
1213 help <<
1214 Allow attaching eBPF programs to a <<
1215 syscall command BPF_PROG_ATTACH. <<
1216 <<
1217 In which context these programs are <<
1218 of attachment. For instance, progra <<
1219 BPF_CGROUP_INET_INGRESS will be exe <<
1220 inet sockets. <<
1221 <<
1222 config CGROUP_MISC <<
1223 bool "Misc resource controller" <<
1224 default n <<
1225 help <<
1226 Provides a controller for miscellan <<
1227 <<
1228 Miscellaneous scalar resources are <<
1229 which cannot be abstracted like the <<
1230 tracks and limits the miscellaneous <<
1231 attached to a cgroup hierarchy. <<
1232 <<
1233 For more information, please check <<
1234 /Documentation/admin-guide/cgroup-v <<
1235 1166
1236 config CGROUP_DEBUG !! 1167 config CHECKPOINT_RESTORE
1237 bool "Debug controller" !! 1168 bool "Checkpoint/restore support" if EXPERT
>> 1169 select PROC_CHILDREN
1238 default n 1170 default n
1239 depends on DEBUG_KERNEL <<
1240 help 1171 help
1241 This option enables a simple contro !! 1172 Enables additional kernel features in a sake of checkpoint/restore.
1242 debugging information about the cgr !! 1173 In particular it adds auxiliary prctl codes to setup process text,
1243 controller is for control cgroup de !! 1174 data and heap segment sizes, and a few additional /proc filesystem
1244 interfaces are not stable. !! 1175 entries.
1245 <<
1246 Say N. <<
1247 <<
1248 config SOCK_CGROUP_DATA <<
1249 bool <<
1250 default n <<
1251 1176
1252 endif # CGROUPS !! 1177 If unsure, say N here.
1253 1178
1254 menuconfig NAMESPACES 1179 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1180 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1181 depends on MULTIUSER
1257 default !EXPERT 1182 default !EXPERT
1258 help 1183 help
1259 Provides the way to make tasks work 1184 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1185 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1186 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1187 different namespaces.
1263 1188
1264 if NAMESPACES 1189 if NAMESPACES
1265 1190
1266 config UTS_NS 1191 config UTS_NS
1267 bool "UTS namespace" 1192 bool "UTS namespace"
1268 default y 1193 default y
1269 help 1194 help
1270 In this namespace tasks see differe 1195 In this namespace tasks see different info provided with the
1271 uname() system call 1196 uname() system call
1272 1197
1273 config TIME_NS <<
1274 bool "TIME namespace" <<
1275 depends on GENERIC_VDSO_TIME_NS <<
1276 default y <<
1277 help <<
1278 In this namespace boottime and mono <<
1279 The time will keep going with the s <<
1280 <<
1281 config IPC_NS 1198 config IPC_NS
1282 bool "IPC namespace" 1199 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1200 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1201 default y
1285 help 1202 help
1286 In this namespace tasks work with I 1203 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1204 different IPC objects in different namespaces.
1288 1205
1289 config USER_NS 1206 config USER_NS
1290 bool "User namespace" 1207 bool "User namespace"
1291 default n 1208 default n
1292 help 1209 help
1293 This allows containers, i.e. vserve 1210 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1211 to provide different user info for different servers.
1295 1212
1296 When user namespaces are enabled in 1213 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a !! 1214 recommended that the MEMCG and MEMCG_KMEM options also be
1298 user-space use the memory control g !! 1215 enabled and that user-space use the memory control groups to
1299 of memory a memory unprivileged use !! 1216 limit the amount of memory a memory unprivileged users can
>> 1217 use.
1300 1218
1301 If unsure, say N. 1219 If unsure, say N.
1302 1220
1303 config PID_NS 1221 config PID_NS
1304 bool "PID Namespaces" 1222 bool "PID Namespaces"
1305 default y 1223 default y
1306 help 1224 help
1307 Support process id namespaces. Thi 1225 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1226 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1227 pid namespaces. This is a building block of containers.
1310 1228
1311 config NET_NS 1229 config NET_NS
1312 bool "Network namespace" 1230 bool "Network namespace"
1313 depends on NET 1231 depends on NET
1314 default y 1232 default y
1315 help 1233 help
1316 Allow user space to create what app 1234 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1235 of the network stack.
1318 1236
1319 endif # NAMESPACES 1237 endif # NAMESPACES
1320 1238
1321 config CHECKPOINT_RESTORE <<
1322 bool "Checkpoint/restore support" <<
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN <<
1325 select KCMP <<
1326 default n <<
1327 help <<
1328 Enables additional kernel features <<
1329 In particular it adds auxiliary prc <<
1330 data and heap segment sizes, and a <<
1331 entries. <<
1332 <<
1333 If unsure, say N here. <<
1334 <<
1335 config SCHED_AUTOGROUP 1239 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1240 bool "Automatic process group scheduling"
1337 select CGROUPS 1241 select CGROUPS
1338 select CGROUP_SCHED 1242 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1243 select FAIR_GROUP_SCHED
1340 help 1244 help
1341 This option optimizes the scheduler 1245 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1246 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1247 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1248 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1249 upon task session.
1346 1250
>> 1251 config SYSFS_DEPRECATED
>> 1252 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1253 depends on SYSFS
>> 1254 default n
>> 1255 help
>> 1256 This option adds code that switches the layout of the "block" class
>> 1257 devices, to not show up in /sys/class/block/, but only in
>> 1258 /sys/block/.
>> 1259
>> 1260 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1261 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1262
>> 1263 This option allows new kernels to run on old distributions and tools,
>> 1264 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1265 major distributions and tools handle this just fine.
>> 1266
>> 1267 Recent distributions and userspace tools after 2009/2010 depend on
>> 1268 the existence of /sys/class/block/, and will not work with this
>> 1269 option enabled.
>> 1270
>> 1271 Only if you are using a new kernel on an old distribution, you might
>> 1272 need to say Y here.
>> 1273
>> 1274 config SYSFS_DEPRECATED_V2
>> 1275 bool "Enable deprecated sysfs features by default"
>> 1276 default n
>> 1277 depends on SYSFS
>> 1278 depends on SYSFS_DEPRECATED
>> 1279 help
>> 1280 Enable deprecated sysfs by default.
>> 1281
>> 1282 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1283 option.
>> 1284
>> 1285 Only if you are using a new kernel on an old distribution, you might
>> 1286 need to say Y here. Even then, odds are you would not need it
>> 1287 enabled, you can always pass the boot option if absolutely necessary.
>> 1288
1347 config RELAY 1289 config RELAY
1348 bool "Kernel->user space relay suppor 1290 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK <<
1350 help 1291 help
1351 This option enables support for rel 1292 This option enables support for relay interface support in
1352 certain file systems (such as debug 1293 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1294 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1295 facilities to relay large amounts of data from kernel space to
1355 user space. 1296 user space.
1356 1297
1357 If unsure, say N. 1298 If unsure, say N.
1358 1299
1359 config BLK_DEV_INITRD 1300 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1301 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
>> 1302 depends on BROKEN || !FRV
1361 help 1303 help
1362 The initial RAM filesystem is a ram 1304 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1305 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1306 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1307 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- !! 1308 etc. See <file:Documentation/initrd.txt> for details.
1367 1309
1368 If RAM disk support (BLK_DEV_RAM) i 1310 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1311 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1312 15 Kbytes (more on some other architectures) to the kernel size.
1371 1313
1372 If unsure say Y. 1314 If unsure say Y.
1373 1315
1374 if BLK_DEV_INITRD 1316 if BLK_DEV_INITRD
1375 1317
1376 source "usr/Kconfig" 1318 source "usr/Kconfig"
1377 1319
1378 endif 1320 endif
1379 1321
1380 config BOOT_CONFIG <<
1381 bool "Boot config support" <<
1382 select BLK_DEV_INITRD if !BOOT_CONFIG <<
1383 help <<
1384 Extra boot config allows system adm <<
1385 complemental extension of kernel cm <<
1386 The boot config file must be attach <<
1387 with checksum, size and magic word. <<
1388 See <file:Documentation/admin-guide <<
1389 <<
1390 If unsure, say Y. <<
1391 <<
1392 config BOOT_CONFIG_FORCE <<
1393 bool "Force unconditional bootconfig <<
1394 depends on BOOT_CONFIG <<
1395 default y if BOOT_CONFIG_EMBED <<
1396 help <<
1397 With this Kconfig option set, BOOT_ <<
1398 out even when the "bootconfig" kern <<
1399 In fact, with this Kconfig option s <<
1400 make the kernel ignore the BOOT_CON <<
1401 parameters. <<
1402 <<
1403 If unsure, say N. <<
1404 <<
1405 config BOOT_CONFIG_EMBED <<
1406 bool "Embed bootconfig file in the ke <<
1407 depends on BOOT_CONFIG <<
1408 help <<
1409 Embed a bootconfig file given by BO <<
1410 kernel. Usually, the bootconfig fil <<
1411 image. But if the system doesn't su <<
1412 help you by embedding a bootconfig <<
1413 <<
1414 If unsure, say N. <<
1415 <<
1416 config BOOT_CONFIG_EMBED_FILE <<
1417 string "Embedded bootconfig file path <<
1418 depends on BOOT_CONFIG_EMBED <<
1419 help <<
1420 Specify a bootconfig file which wil <<
1421 This bootconfig will be used if the <<
1422 bootconfig in the initrd. <<
1423 <<
1424 config INITRAMFS_PRESERVE_MTIME <<
1425 bool "Preserve cpio archive mtimes in <<
1426 default y <<
1427 help <<
1428 Each entry in an initramfs cpio arc <<
1429 enabled, extracted cpio items take <<
1430 setting deferred until after creati <<
1431 <<
1432 If unsure, say Y. <<
1433 <<
1434 choice 1322 choice
1435 prompt "Compiler optimization level" 1323 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE !! 1324 default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
1437 1325
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1326 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" !! 1327 bool "Optimize for performance"
1440 help 1328 help
1441 This is the default optimization le 1329 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1330 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1331 helpful compile-time warnings.
1444 1332
1445 config CC_OPTIMIZE_FOR_SIZE 1333 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" !! 1334 bool "Optimize for size"
1447 help 1335 help
1448 Choosing this option will pass "-Os !! 1336 Enabling this option will pass "-Os" instead of "-O2" to
1449 in a smaller kernel. !! 1337 your compiler resulting in a smaller kernel.
>> 1338
>> 1339 If unsure, say N.
1450 1340
1451 endchoice 1341 endchoice
1452 1342
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION !! 1343 config SYSCTL
1454 bool 1344 bool
1455 help <<
1456 This requires that the arch annotat <<
1457 its external entry points from bein <<
1458 must also merge .text.*, .data.*, a <<
1459 output sections. Care must be taken <<
1460 sections (e.g., '.text.init'). Typi <<
1461 is used to distinguish them from la <<
1462 <<
1463 config LD_DEAD_CODE_DATA_ELIMINATION <<
1464 bool "Dead code and data elimination <<
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI <<
1466 depends on EXPERT <<
1467 depends on $(cc-option,-ffunction-sec <<
1468 depends on $(ld-option,--gc-sections) <<
1469 help <<
1470 Enable this if you want to do dead <<
1471 the linker by compiling with -ffunc <<
1472 and linking with --gc-sections. <<
1473 <<
1474 This can reduce on disk and in-memo <<
1475 code and static data, particularly <<
1476 on small systems. This has the poss <<
1477 silently broken kernel if the requi <<
1478 present. This option is not well te <<
1479 own risk. <<
1480 <<
1481 config LD_ORPHAN_WARN <<
1482 def_bool y <<
1483 depends on ARCH_WANT_LD_ORPHAN_WARN <<
1484 depends on $(ld-option,--orphan-handl <<
1485 depends on $(ld-option,--orphan-handl <<
1486 <<
1487 config LD_ORPHAN_WARN_LEVEL <<
1488 string <<
1489 depends on LD_ORPHAN_WARN <<
1490 default "error" if WERROR <<
1491 default "warn" <<
1492 1345
1493 config SYSCTL !! 1346 config ANON_INODES
1494 bool 1347 bool
1495 1348
1496 config HAVE_UID16 1349 config HAVE_UID16
1497 bool 1350 bool
1498 1351
1499 config SYSCTL_EXCEPTION_TRACE 1352 config SYSCTL_EXCEPTION_TRACE
1500 bool 1353 bool
1501 help 1354 help
1502 Enable support for /proc/sys/debug/ 1355 Enable support for /proc/sys/debug/exception-trace.
1503 1356
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1357 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1358 bool
1506 help 1359 help
1507 Enable support for /proc/sys/kernel 1360 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1361 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1362 about unaligned access emulation going on under the hood.
1510 1363
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1364 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1365 bool
1513 help 1366 help
1514 Enable support for /proc/sys/kernel 1367 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1368 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1369 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1370 see arch/parisc/kernel/unaligned.c for reference
1518 1371
1519 config HAVE_PCSPKR_PLATFORM 1372 config HAVE_PCSPKR_PLATFORM
1520 bool 1373 bool
1521 1374
>> 1375 # interpreter that classic socket filters depend on
>> 1376 config BPF
>> 1377 bool
>> 1378
1522 menuconfig EXPERT 1379 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1380 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1381 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1382 select DEBUG_KERNEL
1526 help 1383 help
1527 This option allows certain base ker 1384 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is !! 1385 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " !! 1386 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh !! 1387 Only use this if you really know what you are doing.
1531 1388
1532 config UID16 1389 config UID16
1533 bool "Enable 16-bit UID system calls" 1390 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1391 depends on HAVE_UID16 && MULTIUSER
1535 default y 1392 default y
1536 help 1393 help
1537 This enables the legacy 16-bit UID 1394 This enables the legacy 16-bit UID syscall wrappers.
1538 1395
1539 config MULTIUSER 1396 config MULTIUSER
1540 bool "Multiple users, groups and capa 1397 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1398 default y
1542 help 1399 help
1543 This option enables support for non 1400 This option enables support for non-root users, groups and
1544 capabilities. 1401 capabilities.
1545 1402
1546 If you say N here, all processes wi 1403 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1404 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1405 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1406 setgid, and capset.
1550 1407
1551 If unsure, say Y here. 1408 If unsure, say Y here.
1552 1409
1553 config SGETMASK_SYSCALL 1410 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1411 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1412 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1556 help !! 1413 ---help---
1557 sys_sgetmask and sys_ssetmask are o 1414 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1415 no longer supported in libc but still enabled by default in some
1559 architectures. 1416 architectures.
1560 1417
1561 If unsure, leave the default option 1418 If unsure, leave the default option here.
1562 1419
1563 config SYSFS_SYSCALL 1420 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1421 bool "Sysfs syscall support" if EXPERT
1565 default y 1422 default y
1566 help !! 1423 ---help---
1567 sys_sysfs is an obsolete system cal 1424 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1425 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1426 compatibility with some systems.
1570 1427
1571 If unsure say Y here. 1428 If unsure say Y here.
1572 1429
1573 config FHANDLE !! 1430 config SYSCTL_SYSCALL
1574 bool "open by fhandle syscalls" if EX !! 1431 bool "Sysctl syscall support" if EXPERT
1575 select EXPORTFS !! 1432 depends on PROC_SYSCTL
1576 default y !! 1433 default n
1577 help !! 1434 select SYSCTL
1578 If you say Y here, a user level pro !! 1435 ---help---
1579 file names to handle and then later !! 1436 sys_sysctl uses binary paths that have been found challenging
1580 different file system operations. T !! 1437 to properly maintain and use. The interface in /proc/sys
1581 userspace file servers, which now t !! 1438 using paths with ascii names is now the primary path to this
1582 of names. The handle would remain t !! 1439 information.
1583 get renamed. Enables open_by_handle !! 1440
1584 syscalls. !! 1441 Almost nothing using the binary sysctl interface so if you are
>> 1442 trying to save some space it is probably safe to disable this,
>> 1443 making your kernel marginally smaller.
1585 1444
1586 config POSIX_TIMERS !! 1445 If unsure say N here.
1587 bool "Posix Clocks & timers" if EXPER !! 1446
1588 default y !! 1447 config KALLSYMS
>> 1448 bool "Load all symbols for debugging/ksymoops" if EXPERT
>> 1449 default y
>> 1450 help
>> 1451 Say Y here to let the kernel print out symbolic crash information and
>> 1452 symbolic stack backtraces. This increases the size of the kernel
>> 1453 somewhat, as all symbols have to be loaded into the kernel image.
>> 1454
>> 1455 config KALLSYMS_ALL
>> 1456 bool "Include all symbols in kallsyms"
>> 1457 depends on DEBUG_KERNEL && KALLSYMS
1589 help 1458 help
1590 This includes native support for PO !! 1459 Normally kallsyms only contains the symbols of functions for nicer
1591 Some embedded systems have no use f !! 1460 OOPS messages and backtraces (i.e., symbols from the text and inittext
1592 can be configured out to reduce the !! 1461 sections). This is sufficient for most cases. And only in very rare
1593 !! 1462 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1594 When this option is disabled, the f !! 1463 names of variables from the data sections, etc).
1595 available: timer_create, timer_gett !! 1464
1596 timer_settime, timer_delete, clock_ !! 1465 This option makes sure that all symbols are loaded into the kernel
1597 setitimer, alarm. Furthermore, the !! 1466 image (i.e., symbols from all sections) in cost of increased kernel
1598 clock_getres and clock_nanosleep sy !! 1467 size (depending on the kernel configuration, it may be 300KiB or
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and !! 1468 something like this).
1600 1469
1601 If unsure say y. !! 1470 Say N unless you really need all symbols.
1602 1471
1603 config PRINTK 1472 config PRINTK
1604 default y 1473 default y
1605 bool "Enable support for printk" if E 1474 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1475 select IRQ_WORK
1607 help 1476 help
1608 This option enables normal printk s 1477 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1478 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1479 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1480 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1481 strongly discouraged.
1613 1482
1614 config BUG 1483 config BUG
1615 bool "BUG() support" if EXPERT 1484 bool "BUG() support" if EXPERT
1616 default y 1485 default y
1617 help 1486 help
1618 Disabling this option eliminates su !! 1487 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p !! 1488 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou !! 1489 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no !! 1490 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. !! 1491 Just say Y.
1623 1492
1624 config ELF_CORE 1493 config ELF_CORE
1625 depends on COREDUMP 1494 depends on COREDUMP
1626 default y 1495 default y
1627 bool "Enable ELF core dumps" if EXPER 1496 bool "Enable ELF core dumps" if EXPERT
1628 help 1497 help
1629 Enable support for generating core 1498 Enable support for generating core dumps. Disabling saves about 4k.
1630 1499
1631 1500
1632 config PCSPKR_PLATFORM 1501 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1502 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1503 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1504 select I8253_LOCK
1636 default y 1505 default y
1637 help 1506 help
1638 This option allows to disable the i !! 1507 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. !! 1508 support, saving some memory.
1640 1509
1641 config BASE_SMALL !! 1510 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1511 default y
>> 1512 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1513 help
1644 Enabling this option reduces the si !! 1514 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1515 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1516 but may reduce performance.
1647 1517
1648 config FUTEX 1518 config FUTEX
1649 bool "Enable futex support" if EXPERT 1519 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1520 default y
1652 imply RT_MUTEXES !! 1521 select RT_MUTEXES
1653 help 1522 help
1654 Disabling this option will cause th 1523 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1524 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1525 run glibc-based applications correctly.
1657 1526
1658 config FUTEX_PI !! 1527 config HAVE_FUTEX_CMPXCHG
1659 bool 1528 bool
1660 depends on FUTEX && RT_MUTEXES !! 1529 depends on FUTEX
1661 default y !! 1530 help
>> 1531 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1532 is implemented and always working. This removes a couple of runtime
>> 1533 checks.
1662 1534
1663 config EPOLL 1535 config EPOLL
1664 bool "Enable eventpoll support" if EX 1536 bool "Enable eventpoll support" if EXPERT
1665 default y 1537 default y
>> 1538 select ANON_INODES
1666 help 1539 help
1667 Disabling this option will cause th 1540 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1541 support for epoll family of system calls.
1669 1542
1670 config SIGNALFD 1543 config SIGNALFD
1671 bool "Enable signalfd() system call" 1544 bool "Enable signalfd() system call" if EXPERT
>> 1545 select ANON_INODES
1672 default y 1546 default y
1673 help 1547 help
1674 Enable the signalfd() system call t 1548 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1549 on a file descriptor.
1676 1550
1677 If unsure, say Y. 1551 If unsure, say Y.
1678 1552
1679 config TIMERFD 1553 config TIMERFD
1680 bool "Enable timerfd() system call" i 1554 bool "Enable timerfd() system call" if EXPERT
>> 1555 select ANON_INODES
1681 default y 1556 default y
1682 help 1557 help
1683 Enable the timerfd() system call th 1558 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1559 events on a file descriptor.
1685 1560
1686 If unsure, say Y. 1561 If unsure, say Y.
1687 1562
1688 config EVENTFD 1563 config EVENTFD
1689 bool "Enable eventfd() system call" i 1564 bool "Enable eventfd() system call" if EXPERT
>> 1565 select ANON_INODES
1690 default y 1566 default y
1691 help 1567 help
1692 Enable the eventfd() system call th 1568 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1569 kernel notification (ie. KAIO) or userspace notifications.
1694 1570
1695 If unsure, say Y. 1571 If unsure, say Y.
1696 1572
>> 1573 # syscall, maps, verifier
>> 1574 config BPF_SYSCALL
>> 1575 bool "Enable bpf() system call"
>> 1576 select ANON_INODES
>> 1577 select BPF
>> 1578 default n
>> 1579 help
>> 1580 Enable the bpf() system call that allows to manipulate eBPF
>> 1581 programs and maps via file descriptors.
>> 1582
>> 1583 config BPF_JIT_ALWAYS_ON
>> 1584 bool "Permanently enable BPF JIT and remove BPF interpreter"
>> 1585 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
>> 1586 help
>> 1587 Enables BPF JIT and removes BPF interpreter to avoid
>> 1588 speculative execution of BPF instructions by the interpreter
>> 1589
1697 config SHMEM 1590 config SHMEM
1698 bool "Use full shmem filesystem" if E 1591 bool "Use full shmem filesystem" if EXPERT
1699 default y 1592 default y
1700 depends on MMU 1593 depends on MMU
1701 help 1594 help
1702 The shmem is an internal filesystem 1595 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1596 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1597 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1598 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1599 which may be appropriate on small systems without swap.
1707 1600
1708 config AIO 1601 config AIO
1709 bool "Enable AIO support" if EXPERT 1602 bool "Enable AIO support" if EXPERT
1710 default y 1603 default y
1711 help 1604 help
1712 This option enables POSIX asynchron 1605 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1606 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1607 this option saves about 7k.
1715 1608
1716 config IO_URING <<
1717 bool "Enable IO uring support" if EXP <<
1718 select IO_WQ <<
1719 default y <<
1720 help <<
1721 This option enables support for the <<
1722 applications to submit and complete <<
1723 completion rings that are shared be <<
1724 <<
1725 config GCOV_PROFILE_URING <<
1726 bool "Enable GCOV profiling on the io <<
1727 depends on GCOV_KERNEL <<
1728 help <<
1729 Enable GCOV profiling on the io_uri <<
1730 code coverage testing. <<
1731 <<
1732 If unsure, say N. <<
1733 <<
1734 Note that this will have a negative <<
1735 the io_uring subsystem, hence this <<
1736 specific test purposes. <<
1737 <<
1738 config ADVISE_SYSCALLS 1609 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1610 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1611 default y
1741 help 1612 help
1742 This option enables the madvise and 1613 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1614 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1615 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1616 applications use these syscalls, you can disable this option to save
1746 space. 1617 space.
1747 1618
>> 1619 config USERFAULTFD
>> 1620 bool "Enable userfaultfd() system call"
>> 1621 select ANON_INODES
>> 1622 depends on MMU
>> 1623 help
>> 1624 Enable the userfaultfd() system call that allows to intercept and
>> 1625 handle page faults in userland.
>> 1626
>> 1627 config PCI_QUIRKS
>> 1628 default y
>> 1629 bool "Enable PCI quirk workarounds" if EXPERT
>> 1630 depends on PCI
>> 1631 help
>> 1632 This enables workarounds for various PCI chipset
>> 1633 bugs/quirks. Disable this only if your target machine is
>> 1634 unaffected by PCI quirks.
>> 1635
1748 config MEMBARRIER 1636 config MEMBARRIER
1749 bool "Enable membarrier() system call 1637 bool "Enable membarrier() system call" if EXPERT
1750 default y 1638 default y
1751 help 1639 help
1752 Enable the membarrier() system call 1640 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1641 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1642 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1643 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1644 compiler barrier.
1757 1645
1758 If unsure, say Y. 1646 If unsure, say Y.
1759 1647
1760 config KCMP !! 1648 config EMBEDDED
1761 bool "Enable kcmp() system call" if E !! 1649 bool "Embedded system"
1762 help !! 1650 option allnoconfig_y
1763 Enable the kernel resource comparis !! 1651 select EXPERT
1764 user-space with the ability to comp !! 1652 help
1765 share a common resource, such as a !! 1653 This option should be enabled if compiling the kernel for
1766 memory space. !! 1654 an embedded system so certain expert options are available
1767 !! 1655 for configuration.
1768 If unsure, say N. <<
1769 <<
1770 config RSEQ <<
1771 bool "Enable rseq() system call" if E <<
1772 default y <<
1773 depends on HAVE_RSEQ <<
1774 select MEMBARRIER <<
1775 help <<
1776 Enable the restartable sequences sy <<
1777 user-space cache for the current CP <<
1778 speeds up getting the current CPU n <<
1779 as well as an ABI to speed up user- <<
1780 per-CPU data. <<
1781 <<
1782 If unsure, say Y. <<
1783 <<
1784 config DEBUG_RSEQ <<
1785 default n <<
1786 bool "Enable debugging of rseq() syst <<
1787 depends on RSEQ && DEBUG_KERNEL <<
1788 help <<
1789 Enable extra debugging checks for t <<
1790 <<
1791 If unsure, say N. <<
1792 <<
1793 config CACHESTAT_SYSCALL <<
1794 bool "Enable cachestat() system call" <<
1795 default y <<
1796 help <<
1797 Enable the cachestat system call, w <<
1798 statistics of a file (number of cac <<
1799 pages marked for writeback, (recent <<
1800 <<
1801 If unsure say Y here. <<
1802 <<
1803 config PC104 <<
1804 bool "PC/104 support" if EXPERT <<
1805 help <<
1806 Expose PC/104 form factor device dr <<
1807 selection and configuration. Enable <<
1808 machine has a PC/104 bus. <<
1809 <<
1810 config KALLSYMS <<
1811 bool "Load all symbols for debugging/ <<
1812 default y <<
1813 help <<
1814 Say Y here to let the kernel print <<
1815 symbolic stack backtraces. This inc <<
1816 somewhat, as all symbols have to be <<
1817 <<
1818 config KALLSYMS_SELFTEST <<
1819 bool "Test the basic functions and pe <<
1820 depends on KALLSYMS <<
1821 default n <<
1822 help <<
1823 Test the basic functions and perfor <<
1824 kallsyms_lookup_name. It also calcu <<
1825 kallsyms compression algorithm for <<
1826 <<
1827 Start self-test automatically after <<
1828 "dmesg | grep kallsyms_selftest" to <<
1829 displayed in the last line, indicat <<
1830 <<
1831 config KALLSYMS_ALL <<
1832 bool "Include all symbols in kallsyms <<
1833 depends on DEBUG_KERNEL && KALLSYMS <<
1834 help <<
1835 Normally kallsyms only contains the <<
1836 OOPS messages and backtraces (i.e., <<
1837 sections). This is sufficient for m <<
1838 enable kernel live patching, or oth <<
1839 when a debugger is used) all symbol <<
1840 variables from the data sections, e <<
1841 <<
1842 This option makes sure that all sym <<
1843 image (i.e., symbols from all secti <<
1844 size (depending on the kernel confi <<
1845 something like this). <<
1846 <<
1847 Say N unless you really need all sy <<
1848 <<
1849 config KALLSYMS_ABSOLUTE_PERCPU <<
1850 bool <<
1851 depends on KALLSYMS <<
1852 default X86_64 && SMP <<
1853 <<
1854 # end of the "standard kernel features (exper <<
1855 <<
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS <<
1857 bool <<
1858 <<
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE <<
1860 bool <<
1861 1656
1862 config HAVE_PERF_EVENTS 1657 config HAVE_PERF_EVENTS
1863 bool 1658 bool
1864 help 1659 help
1865 See tools/perf/design.txt for detai 1660 See tools/perf/design.txt for details.
1866 1661
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1662 config PERF_USE_VMALLOC
1872 bool 1663 bool
1873 help 1664 help
1874 See tools/perf/design.txt for detai 1665 See tools/perf/design.txt for details
1875 1666
1876 menu "Kernel Performance Events And Counters" 1667 menu "Kernel Performance Events And Counters"
1877 1668
1878 config PERF_EVENTS 1669 config PERF_EVENTS
1879 bool "Kernel performance events and c 1670 bool "Kernel performance events and counters"
1880 default y if PROFILING 1671 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1672 depends on HAVE_PERF_EVENTS
>> 1673 select ANON_INODES
1882 select IRQ_WORK 1674 select IRQ_WORK
>> 1675 select SRCU
1883 help 1676 help
1884 Enable kernel support for various p 1677 Enable kernel support for various performance events provided
1885 by software and hardware. 1678 by software and hardware.
1886 1679
1887 Software events are supported eithe 1680 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1681 use of generic tracepoints.
1889 1682
1890 Most modern CPUs support performanc 1683 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1684 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1685 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1686 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1687 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1688 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1689 used to profile the code that runs on that CPU.
1897 1690
1898 The Linux Performance Event subsyst 1691 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1692 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1693 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1694 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1695 capabilities on top of those.
1903 1696
1904 Say Y if unsure. 1697 Say Y if unsure.
1905 1698
1906 config DEBUG_PERF_USE_VMALLOC 1699 config DEBUG_PERF_USE_VMALLOC
1907 default n 1700 default n
1908 bool "Debug: use vmalloc to back perf 1701 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1702 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1703 select PERF_USE_VMALLOC
1911 help 1704 help
1912 Use vmalloc memory to back perf mma !! 1705 Use vmalloc memory to back perf mmap() buffers.
1913 1706
1914 Mostly useful for debugging the vma !! 1707 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. !! 1708 that don't require it.
1916 1709
1917 Say N if unsure. !! 1710 Say N if unsure.
1918 1711
1919 endmenu 1712 endmenu
1920 1713
>> 1714 config VM_EVENT_COUNTERS
>> 1715 default y
>> 1716 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1717 help
>> 1718 VM event counters are needed for event counts to be shown.
>> 1719 This option allows the disabling of the VM event counters
>> 1720 on EXPERT systems. /proc/vmstat will only show page counts
>> 1721 if VM event counters are disabled.
>> 1722
>> 1723 config SLUB_DEBUG
>> 1724 default y
>> 1725 bool "Enable SLUB debugging support" if EXPERT
>> 1726 depends on SLUB && SYSFS
>> 1727 help
>> 1728 SLUB has extensive debug support features. Disabling these can
>> 1729 result in significant savings in code size. This also disables
>> 1730 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1731 no support for cache validation etc.
>> 1732
>> 1733 config COMPAT_BRK
>> 1734 bool "Disable heap randomization"
>> 1735 default y
>> 1736 help
>> 1737 Randomizing heap placement makes heap exploits harder, but it
>> 1738 also breaks ancient binaries (including anything libc5 based).
>> 1739 This option changes the bootup default to heap randomization
>> 1740 disabled, and can be overridden at runtime by setting
>> 1741 /proc/sys/kernel/randomize_va_space to 2.
>> 1742
>> 1743 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1744
>> 1745 choice
>> 1746 prompt "Choose SLAB allocator"
>> 1747 default SLUB
>> 1748 help
>> 1749 This option allows to select a slab allocator.
>> 1750
>> 1751 config SLAB
>> 1752 bool "SLAB"
>> 1753 help
>> 1754 The regular slab allocator that is established and known to work
>> 1755 well in all environments. It organizes cache hot objects in
>> 1756 per cpu and per node queues.
>> 1757
>> 1758 config SLUB
>> 1759 bool "SLUB (Unqueued Allocator)"
>> 1760 help
>> 1761 SLUB is a slab allocator that minimizes cache line usage
>> 1762 instead of managing queues of cached objects (SLAB approach).
>> 1763 Per cpu caching is realized using slabs of objects instead
>> 1764 of queues of objects. SLUB can use memory efficiently
>> 1765 and has enhanced diagnostics. SLUB is the default choice for
>> 1766 a slab allocator.
>> 1767
>> 1768 config SLOB
>> 1769 depends on EXPERT
>> 1770 bool "SLOB (Simple Allocator)"
>> 1771 help
>> 1772 SLOB replaces the stock allocator with a drastically simpler
>> 1773 allocator. SLOB is generally more space efficient but
>> 1774 does not perform as well on large systems.
>> 1775
>> 1776 endchoice
>> 1777
>> 1778 config SLUB_CPU_PARTIAL
>> 1779 default y
>> 1780 depends on SLUB && SMP
>> 1781 bool "SLUB per cpu partial cache"
>> 1782 help
>> 1783 Per cpu partial caches accellerate objects allocation and freeing
>> 1784 that is local to a processor at the price of more indeterminism
>> 1785 in the latency of the free. On overflow these caches will be cleared
>> 1786 which requires the taking of locks that may cause latency spikes.
>> 1787 Typically one would choose no for a realtime system.
>> 1788
>> 1789 config MMAP_ALLOW_UNINITIALIZED
>> 1790 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1791 depends on EXPERT && !MMU
>> 1792 default n
>> 1793 help
>> 1794 Normally, and according to the Linux spec, anonymous memory obtained
>> 1795 from mmap() has it's contents cleared before it is passed to
>> 1796 userspace. Enabling this config option allows you to request that
>> 1797 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1798 providing a huge performance boost. If this option is not enabled,
>> 1799 then the flag will be ignored.
>> 1800
>> 1801 This is taken advantage of by uClibc's malloc(), and also by
>> 1802 ELF-FDPIC binfmt's brk and stack allocator.
>> 1803
>> 1804 Because of the obvious security issues, this option should only be
>> 1805 enabled on embedded devices where you control what is run in
>> 1806 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1807 it is normally safe to say Y here.
>> 1808
>> 1809 See Documentation/nommu-mmap.txt for more information.
>> 1810
1921 config SYSTEM_DATA_VERIFICATION 1811 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1812 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1813 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1814 select KEYS
1925 select CRYPTO 1815 select CRYPTO
1926 select CRYPTO_RSA <<
1927 select ASYMMETRIC_KEY_TYPE 1816 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1817 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
>> 1818 select PUBLIC_KEY_ALGO_RSA
1929 select ASN1 1819 select ASN1
1930 select OID_REGISTRY 1820 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1821 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1822 select PKCS7_MESSAGE_PARSER
1933 help 1823 help
1934 Provide PKCS#7 message verification 1824 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1825 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1826 module verification, kexec image verification and firmware blob
1937 verification. 1827 verification.
1938 1828
1939 config PROFILING 1829 config PROFILING
1940 bool "Profiling support" 1830 bool "Profiling support"
1941 help 1831 help
1942 Say Y here to enable the extended p 1832 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. !! 1833 by profilers such as OProfile.
1944 <<
1945 config RUST <<
1946 bool "Rust support" <<
1947 depends on HAVE_RUST <<
1948 depends on RUST_IS_AVAILABLE <<
1949 depends on !MODVERSIONS <<
1950 depends on !GCC_PLUGIN_RANDSTRUCT <<
1951 depends on !RANDSTRUCT <<
1952 depends on !DEBUG_INFO_BTF || PAHOLE_ <<
1953 depends on !CFI_CLANG || HAVE_CFI_ICA <<
1954 select CFI_ICALL_NORMALIZE_INTEGERS i <<
1955 depends on !CALL_PADDING || RUSTC_VER <<
1956 depends on !KASAN_SW_TAGS <<
1957 depends on !(MITIGATION_RETHUNK && KA <<
1958 help <<
1959 Enables Rust support in the kernel. <<
1960 <<
1961 This allows other Rust-related opti <<
1962 to be selected. <<
1963 <<
1964 It is also required to be able to l <<
1965 written in Rust. <<
1966 <<
1967 See Documentation/rust/ for more in <<
1968 <<
1969 If unsure, say N. <<
1970 <<
1971 config RUSTC_VERSION_TEXT <<
1972 string <<
1973 depends on RUST <<
1974 default "$(RUSTC_VERSION_TEXT)" <<
1975 help <<
1976 See `CC_VERSION_TEXT`. <<
1977 <<
1978 config BINDGEN_VERSION_TEXT <<
1979 string <<
1980 depends on RUST <<
1981 # The dummy parameter `workaround-for <<
1982 # (https://github.com/rust-lang/rust- <<
1983 # the minimum version is upgraded pas <<
1984 default "$(shell,$(BINDGEN) --version <<
1985 1834
1986 # 1835 #
1987 # Place an empty function call at each tracep 1836 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1837 # dynamically changed for a probe function.
1989 # 1838 #
1990 config TRACEPOINTS 1839 config TRACEPOINTS
1991 bool 1840 bool
1992 1841
1993 source "kernel/Kconfig.kexec" !! 1842 source "arch/Kconfig"
1994 1843
1995 endmenu # General setup 1844 endmenu # General setup
1996 1845
1997 source "arch/Kconfig" !! 1846 config HAVE_GENERIC_DMA_COHERENT
>> 1847 bool
>> 1848 default n
>> 1849
>> 1850 config SLABINFO
>> 1851 bool
>> 1852 depends on PROC_FS
>> 1853 depends on SLAB || SLUB_DEBUG
>> 1854 default y
1998 1855
1999 config RT_MUTEXES 1856 config RT_MUTEXES
2000 bool 1857 bool
2001 default y if PREEMPT_RT <<
2002 1858
2003 config MODULE_SIG_FORMAT !! 1859 config BASE_SMALL
2004 def_bool n !! 1860 int
>> 1861 default 0 if BASE_FULL
>> 1862 default 1 if !BASE_FULL
>> 1863
>> 1864 menuconfig MODULES
>> 1865 bool "Enable loadable module support"
>> 1866 option modules
>> 1867 help
>> 1868 Kernel modules are small pieces of compiled code which can
>> 1869 be inserted in the running kernel, rather than being
>> 1870 permanently built into the kernel. You use the "modprobe"
>> 1871 tool to add (and sometimes remove) them. If you say Y here,
>> 1872 many parts of the kernel can be built as modules (by
>> 1873 answering M instead of Y where indicated): this is most
>> 1874 useful for infrequently used options which are not required
>> 1875 for booting. For more information, see the man pages for
>> 1876 modprobe, lsmod, modinfo, insmod and rmmod.
>> 1877
>> 1878 If you say Y here, you will need to run "make
>> 1879 modules_install" to put the modules under /lib/modules/
>> 1880 where modprobe can find them (you may need to be root to do
>> 1881 this).
>> 1882
>> 1883 If unsure, say Y.
>> 1884
>> 1885 if MODULES
>> 1886
>> 1887 config MODULE_FORCE_LOAD
>> 1888 bool "Forced module loading"
>> 1889 default n
>> 1890 help
>> 1891 Allow loading of modules without version information (ie. modprobe
>> 1892 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 1893 is usually a really bad idea.
>> 1894
>> 1895 config MODULE_UNLOAD
>> 1896 bool "Module unloading"
>> 1897 help
>> 1898 Without this option you will not be able to unload any
>> 1899 modules (note that some modules may not be unloadable
>> 1900 anyway), which makes your kernel smaller, faster
>> 1901 and simpler. If unsure, say Y.
>> 1902
>> 1903 config MODULE_FORCE_UNLOAD
>> 1904 bool "Forced module unloading"
>> 1905 depends on MODULE_UNLOAD
>> 1906 help
>> 1907 This option allows you to force a module to unload, even if the
>> 1908 kernel believes it is unsafe: the kernel will remove the module
>> 1909 without waiting for anyone to stop using it (using the -f option to
>> 1910 rmmod). This is mainly for kernel developers and desperate users.
>> 1911 If unsure, say N.
>> 1912
>> 1913 config MODVERSIONS
>> 1914 bool "Module versioning support"
>> 1915 help
>> 1916 Usually, you have to use modules compiled with your kernel.
>> 1917 Saying Y here makes it sometimes possible to use modules
>> 1918 compiled for different kernels, by adding enough information
>> 1919 to the modules to (hopefully) spot any changes which would
>> 1920 make them incompatible with the kernel you are running. If
>> 1921 unsure, say N.
>> 1922
>> 1923 config MODULE_SRCVERSION_ALL
>> 1924 bool "Source checksum for all modules"
>> 1925 help
>> 1926 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 1927 field inserted into their modinfo section, which contains a
>> 1928 sum of the source files which made it. This helps maintainers
>> 1929 see exactly which source was used to build a module (since
>> 1930 others sometimes change the module source without updating
>> 1931 the version). With this option, such a "srcversion" field
>> 1932 will be created for all modules. If unsure, say N.
>> 1933
>> 1934 config MODULE_SIG
>> 1935 bool "Module signature verification"
>> 1936 depends on MODULES
2005 select SYSTEM_DATA_VERIFICATION 1937 select SYSTEM_DATA_VERIFICATION
>> 1938 help
>> 1939 Check modules for valid signatures upon load: the signature
>> 1940 is simply appended to the module. For more information see
>> 1941 Documentation/module-signing.txt.
>> 1942
>> 1943 Note that this option adds the OpenSSL development packages as a
>> 1944 kernel build dependency so that the signing tool can use its crypto
>> 1945 library.
>> 1946
>> 1947 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 1948 module DOES NOT get stripped after being signed. This includes the
>> 1949 debuginfo strip done by some packagers (such as rpmbuild) and
>> 1950 inclusion into an initramfs that wants the module size reduced.
>> 1951
>> 1952 config MODULE_SIG_FORCE
>> 1953 bool "Require modules to be validly signed"
>> 1954 depends on MODULE_SIG
>> 1955 help
>> 1956 Reject unsigned modules or signed modules for which we don't have a
>> 1957 key. Without this, such modules will simply taint the kernel.
>> 1958
>> 1959 config MODULE_SIG_ALL
>> 1960 bool "Automatically sign all modules"
>> 1961 default y
>> 1962 depends on MODULE_SIG
>> 1963 help
>> 1964 Sign all modules during make modules_install. Without this option,
>> 1965 modules must be signed manually, using the scripts/sign-file tool.
2006 1966
2007 source "kernel/module/Kconfig" !! 1967 comment "Do not forget to sign required modules with scripts/sign-file"
>> 1968 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 1969
>> 1970 choice
>> 1971 prompt "Which hash algorithm should modules be signed with?"
>> 1972 depends on MODULE_SIG
>> 1973 help
>> 1974 This determines which sort of hashing algorithm will be used during
>> 1975 signature generation. This algorithm _must_ be built into the kernel
>> 1976 directly so that signature verification can take place. It is not
>> 1977 possible to load a signed module containing the algorithm to check
>> 1978 the signature on that module.
>> 1979
>> 1980 config MODULE_SIG_SHA1
>> 1981 bool "Sign modules with SHA-1"
>> 1982 select CRYPTO_SHA1
>> 1983
>> 1984 config MODULE_SIG_SHA224
>> 1985 bool "Sign modules with SHA-224"
>> 1986 select CRYPTO_SHA256
>> 1987
>> 1988 config MODULE_SIG_SHA256
>> 1989 bool "Sign modules with SHA-256"
>> 1990 select CRYPTO_SHA256
>> 1991
>> 1992 config MODULE_SIG_SHA384
>> 1993 bool "Sign modules with SHA-384"
>> 1994 select CRYPTO_SHA512
>> 1995
>> 1996 config MODULE_SIG_SHA512
>> 1997 bool "Sign modules with SHA-512"
>> 1998 select CRYPTO_SHA512
>> 1999
>> 2000 endchoice
>> 2001
>> 2002 config MODULE_SIG_HASH
>> 2003 string
>> 2004 depends on MODULE_SIG
>> 2005 default "sha1" if MODULE_SIG_SHA1
>> 2006 default "sha224" if MODULE_SIG_SHA224
>> 2007 default "sha256" if MODULE_SIG_SHA256
>> 2008 default "sha384" if MODULE_SIG_SHA384
>> 2009 default "sha512" if MODULE_SIG_SHA512
>> 2010
>> 2011 config MODULE_COMPRESS
>> 2012 bool "Compress modules on installation"
>> 2013 depends on MODULES
>> 2014 help
>> 2015
>> 2016 Compresses kernel modules when 'make modules_install' is run; gzip or
>> 2017 xz depending on "Compression algorithm" below.
>> 2018
>> 2019 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
>> 2020
>> 2021 Out-of-tree kernel modules installed using Kbuild will also be
>> 2022 compressed upon installation.
>> 2023
>> 2024 Note: for modules inside an initrd or initramfs, it's more efficient
>> 2025 to compress the whole initrd or initramfs instead.
>> 2026
>> 2027 Note: This is fully compatible with signed modules.
>> 2028
>> 2029 If in doubt, say N.
>> 2030
>> 2031 choice
>> 2032 prompt "Compression algorithm"
>> 2033 depends on MODULE_COMPRESS
>> 2034 default MODULE_COMPRESS_GZIP
>> 2035 help
>> 2036 This determines which sort of compression will be used during
>> 2037 'make modules_install'.
>> 2038
>> 2039 GZIP (default) and XZ are supported.
>> 2040
>> 2041 config MODULE_COMPRESS_GZIP
>> 2042 bool "GZIP"
>> 2043
>> 2044 config MODULE_COMPRESS_XZ
>> 2045 bool "XZ"
>> 2046
>> 2047 endchoice
>> 2048
>> 2049 endif # MODULES
>> 2050
>> 2051 config MODULES_TREE_LOOKUP
>> 2052 def_bool y
>> 2053 depends on PERF_EVENTS || TRACING
2008 2054
2009 config INIT_ALL_POSSIBLE 2055 config INIT_ALL_POSSIBLE
2010 bool 2056 bool
2011 help 2057 help
2012 Back when each arch used to define 2058 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2059 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2060 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2061 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2062 and have several arch maintainers pursuing me down dark alleys.
2017 2063
2018 source "block/Kconfig" 2064 source "block/Kconfig"
2019 2065
2020 config PREEMPT_NOTIFIERS 2066 config PREEMPT_NOTIFIERS
2021 bool 2067 bool
2022 2068
2023 config PADATA 2069 config PADATA
2024 depends on SMP 2070 depends on SMP
2025 bool 2071 bool
2026 2072
>> 2073 # Can be selected by architectures with broken toolchains
>> 2074 # that get confused by correct const<->read_only section
>> 2075 # mappings
>> 2076 config BROKEN_RODATA
>> 2077 bool
>> 2078
2027 config ASN1 2079 config ASN1
2028 tristate 2080 tristate
2029 help 2081 help
2030 Build a simple ASN.1 grammar compil 2082 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2083 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2084 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2085 functions to call on what tags.
2034 2086
2035 source "kernel/Kconfig.locks" 2087 source "kernel/Kconfig.locks"
2036 <<
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE <<
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool <<
2042 <<
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE <<
2044 bool <<
2045 <<
2046 # It may be useful for an architecture to ove <<
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma <<
2048 # and the COMPAT_ variants in <linux/compat.h <<
2049 # different calling convention for syscalls. <<
2050 # macros for not-implemented syscalls in kern <<
2051 # kernel/time/posix-stubs.c. All these overri <<
2052 # <asm/syscall_wrapper.h>. <<
2053 config ARCH_HAS_SYSCALL_WRAPPER <<
2054 def_bool n <<
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