| 1 | config ARCH |
| 2 | string |
| 3 | option env="ARCH" |
| 4 | |
| 5 | config KERNELVERSION |
| 6 | string |
| 7 | option env="KERNELVERSION" |
| 8 | |
| 9 | config DEFCONFIG_LIST |
| 10 | string |
| 11 | depends on !UML |
| 12 | option defconfig_list |
| 13 | default "/lib/modules/$UNAME_RELEASE/.config" |
| 14 | default "/etc/kernel-config" |
| 15 | default "/boot/config-$UNAME_RELEASE" |
| 16 | default "$ARCH_DEFCONFIG" |
| 17 | default "arch/$ARCH/defconfig" |
| 18 | |
| 19 | config CONSTRUCTORS |
| 20 | bool |
| 21 | depends on !UML |
| 22 | |
| 23 | config IRQ_WORK |
| 24 | bool |
| 25 | |
| 26 | config BUILDTIME_EXTABLE_SORT |
| 27 | bool |
| 28 | |
| 29 | menu "General setup" |
| 30 | |
| 31 | config BROKEN |
| 32 | bool |
| 33 | |
| 34 | config BROKEN_ON_SMP |
| 35 | bool |
| 36 | depends on BROKEN || !SMP |
| 37 | default y |
| 38 | |
| 39 | config INIT_ENV_ARG_LIMIT |
| 40 | int |
| 41 | default 32 if !UML |
| 42 | default 128 if UML |
| 43 | help |
| 44 | Maximum of each of the number of arguments and environment |
| 45 | variables passed to init from the kernel command line. |
| 46 | |
| 47 | |
| 48 | config CROSS_COMPILE |
| 49 | string "Cross-compiler tool prefix" |
| 50 | help |
| 51 | Same as running 'make CROSS_COMPILE=prefix-' but stored for |
| 52 | default make runs in this kernel build directory. You don't |
| 53 | need to set this unless you want the configured kernel build |
| 54 | directory to select the cross-compiler automatically. |
| 55 | |
| 56 | config COMPILE_TEST |
| 57 | bool "Compile also drivers which will not load" |
| 58 | default n |
| 59 | help |
| 60 | Some drivers can be compiled on a different platform than they are |
| 61 | intended to be run on. Despite they cannot be loaded there (or even |
| 62 | when they load they cannot be used due to missing HW support), |
| 63 | developers still, opposing to distributors, might want to build such |
| 64 | drivers to compile-test them. |
| 65 | |
| 66 | If you are a developer and want to build everything available, say Y |
| 67 | here. If you are a user/distributor, say N here to exclude useless |
| 68 | drivers to be distributed. |
| 69 | |
| 70 | config LOCALVERSION |
| 71 | string "Local version - append to kernel release" |
| 72 | help |
| 73 | Append an extra string to the end of your kernel version. |
| 74 | This will show up when you type uname, for example. |
| 75 | The string you set here will be appended after the contents of |
| 76 | any files with a filename matching localversion* in your |
| 77 | object and source tree, in that order. Your total string can |
| 78 | be a maximum of 64 characters. |
| 79 | |
| 80 | config LOCALVERSION_AUTO |
| 81 | bool "Automatically append version information to the version string" |
| 82 | default y |
| 83 | help |
| 84 | This will try to automatically determine if the current tree is a |
| 85 | release tree by looking for git tags that belong to the current |
| 86 | top of tree revision. |
| 87 | |
| 88 | A string of the format -gxxxxxxxx will be added to the localversion |
| 89 | if a git-based tree is found. The string generated by this will be |
| 90 | appended after any matching localversion* files, and after the value |
| 91 | set in CONFIG_LOCALVERSION. |
| 92 | |
| 93 | (The actual string used here is the first eight characters produced |
| 94 | by running the command: |
| 95 | |
| 96 | $ git rev-parse --verify HEAD |
| 97 | |
| 98 | which is done within the script "scripts/setlocalversion".) |
| 99 | |
| 100 | config HAVE_KERNEL_GZIP |
| 101 | bool |
| 102 | |
| 103 | config HAVE_KERNEL_BZIP2 |
| 104 | bool |
| 105 | |
| 106 | config HAVE_KERNEL_LZMA |
| 107 | bool |
| 108 | |
| 109 | config HAVE_KERNEL_XZ |
| 110 | bool |
| 111 | |
| 112 | config HAVE_KERNEL_LZO |
| 113 | bool |
| 114 | |
| 115 | config HAVE_KERNEL_LZ4 |
| 116 | bool |
| 117 | |
| 118 | choice |
| 119 | prompt "Kernel compression mode" |
| 120 | default KERNEL_GZIP |
| 121 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 |
| 122 | help |
| 123 | The linux kernel is a kind of self-extracting executable. |
| 124 | Several compression algorithms are available, which differ |
| 125 | in efficiency, compression and decompression speed. |
| 126 | Compression speed is only relevant when building a kernel. |
| 127 | Decompression speed is relevant at each boot. |
| 128 | |
| 129 | If you have any problems with bzip2 or lzma compressed |
| 130 | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older |
| 131 | version of this functionality (bzip2 only), for 2.4, was |
| 132 | supplied by Christian Ludwig) |
| 133 | |
| 134 | High compression options are mostly useful for users, who |
| 135 | are low on disk space (embedded systems), but for whom ram |
| 136 | size matters less. |
| 137 | |
| 138 | If in doubt, select 'gzip' |
| 139 | |
| 140 | config KERNEL_GZIP |
| 141 | bool "Gzip" |
| 142 | depends on HAVE_KERNEL_GZIP |
| 143 | help |
| 144 | The old and tried gzip compression. It provides a good balance |
| 145 | between compression ratio and decompression speed. |
| 146 | |
| 147 | config KERNEL_BZIP2 |
| 148 | bool "Bzip2" |
| 149 | depends on HAVE_KERNEL_BZIP2 |
| 150 | help |
| 151 | Its compression ratio and speed is intermediate. |
| 152 | Decompression speed is slowest among the choices. The kernel |
| 153 | size is about 10% smaller with bzip2, in comparison to gzip. |
| 154 | Bzip2 uses a large amount of memory. For modern kernels you |
| 155 | will need at least 8MB RAM or more for booting. |
| 156 | |
| 157 | config KERNEL_LZMA |
| 158 | bool "LZMA" |
| 159 | depends on HAVE_KERNEL_LZMA |
| 160 | help |
| 161 | This compression algorithm's ratio is best. Decompression speed |
| 162 | is between gzip and bzip2. Compression is slowest. |
| 163 | The kernel size is about 33% smaller with LZMA in comparison to gzip. |
| 164 | |
| 165 | config KERNEL_XZ |
| 166 | bool "XZ" |
| 167 | depends on HAVE_KERNEL_XZ |
| 168 | help |
| 169 | XZ uses the LZMA2 algorithm and instruction set specific |
| 170 | BCJ filters which can improve compression ratio of executable |
| 171 | code. The size of the kernel is about 30% smaller with XZ in |
| 172 | comparison to gzip. On architectures for which there is a BCJ |
| 173 | filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ |
| 174 | will create a few percent smaller kernel than plain LZMA. |
| 175 | |
| 176 | The speed is about the same as with LZMA: The decompression |
| 177 | speed of XZ is better than that of bzip2 but worse than gzip |
| 178 | and LZO. Compression is slow. |
| 179 | |
| 180 | config KERNEL_LZO |
| 181 | bool "LZO" |
| 182 | depends on HAVE_KERNEL_LZO |
| 183 | help |
| 184 | Its compression ratio is the poorest among the choices. The kernel |
| 185 | size is about 10% bigger than gzip; however its speed |
| 186 | (both compression and decompression) is the fastest. |
| 187 | |
| 188 | config KERNEL_LZ4 |
| 189 | bool "LZ4" |
| 190 | depends on HAVE_KERNEL_LZ4 |
| 191 | help |
| 192 | LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. |
| 193 | A preliminary version of LZ4 de/compression tool is available at |
| 194 | <https://code.google.com/p/lz4/>. |
| 195 | |
| 196 | Its compression ratio is worse than LZO. The size of the kernel |
| 197 | is about 8% bigger than LZO. But the decompression speed is |
| 198 | faster than LZO. |
| 199 | |
| 200 | endchoice |
| 201 | |
| 202 | config DEFAULT_HOSTNAME |
| 203 | string "Default hostname" |
| 204 | default "(none)" |
| 205 | help |
| 206 | This option determines the default system hostname before userspace |
| 207 | calls sethostname(2). The kernel traditionally uses "(none)" here, |
| 208 | but you may wish to use a different default here to make a minimal |
| 209 | system more usable with less configuration. |
| 210 | |
| 211 | config SWAP |
| 212 | bool "Support for paging of anonymous memory (swap)" |
| 213 | depends on MMU && BLOCK |
| 214 | default y |
| 215 | help |
| 216 | This option allows you to choose whether you want to have support |
| 217 | for so called swap devices or swap files in your kernel that are |
| 218 | used to provide more virtual memory than the actual RAM present |
| 219 | in your computer. If unsure say Y. |
| 220 | |
| 221 | config SYSVIPC |
| 222 | bool "System V IPC" |
| 223 | ---help--- |
| 224 | Inter Process Communication is a suite of library functions and |
| 225 | system calls which let processes (running programs) synchronize and |
| 226 | exchange information. It is generally considered to be a good thing, |
| 227 | and some programs won't run unless you say Y here. In particular, if |
| 228 | you want to run the DOS emulator dosemu under Linux (read the |
| 229 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), |
| 230 | you'll need to say Y here. |
| 231 | |
| 232 | You can find documentation about IPC with "info ipc" and also in |
| 233 | section 6.4 of the Linux Programmer's Guide, available from |
| 234 | <http://www.tldp.org/guides.html>. |
| 235 | |
| 236 | config SYSVIPC_SYSCTL |
| 237 | bool |
| 238 | depends on SYSVIPC |
| 239 | depends on SYSCTL |
| 240 | default y |
| 241 | |
| 242 | config POSIX_MQUEUE |
| 243 | bool "POSIX Message Queues" |
| 244 | depends on NET |
| 245 | ---help--- |
| 246 | POSIX variant of message queues is a part of IPC. In POSIX message |
| 247 | queues every message has a priority which decides about succession |
| 248 | of receiving it by a process. If you want to compile and run |
| 249 | programs written e.g. for Solaris with use of its POSIX message |
| 250 | queues (functions mq_*) say Y here. |
| 251 | |
| 252 | POSIX message queues are visible as a filesystem called 'mqueue' |
| 253 | and can be mounted somewhere if you want to do filesystem |
| 254 | operations on message queues. |
| 255 | |
| 256 | If unsure, say Y. |
| 257 | |
| 258 | config POSIX_MQUEUE_SYSCTL |
| 259 | bool |
| 260 | depends on POSIX_MQUEUE |
| 261 | depends on SYSCTL |
| 262 | default y |
| 263 | |
| 264 | config FHANDLE |
| 265 | bool "open by fhandle syscalls" |
| 266 | select EXPORTFS |
| 267 | help |
| 268 | If you say Y here, a user level program will be able to map |
| 269 | file names to handle and then later use the handle for |
| 270 | different file system operations. This is useful in implementing |
| 271 | userspace file servers, which now track files using handles instead |
| 272 | of names. The handle would remain the same even if file names |
| 273 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) |
| 274 | syscalls. |
| 275 | |
| 276 | config AUDIT |
| 277 | bool "Auditing support" |
| 278 | depends on NET |
| 279 | help |
| 280 | Enable auditing infrastructure that can be used with another |
| 281 | kernel subsystem, such as SELinux (which requires this for |
| 282 | logging of avc messages output). Does not do system-call |
| 283 | auditing without CONFIG_AUDITSYSCALL. |
| 284 | |
| 285 | config AUDITSYSCALL |
| 286 | bool "Enable system-call auditing support" |
| 287 | depends on AUDIT && (X86 || PARISC || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) |
| 288 | default y if SECURITY_SELINUX |
| 289 | help |
| 290 | Enable low-overhead system-call auditing infrastructure that |
| 291 | can be used independently or with another kernel subsystem, |
| 292 | such as SELinux. |
| 293 | |
| 294 | config AUDIT_WATCH |
| 295 | def_bool y |
| 296 | depends on AUDITSYSCALL |
| 297 | select FSNOTIFY |
| 298 | |
| 299 | config AUDIT_TREE |
| 300 | def_bool y |
| 301 | depends on AUDITSYSCALL |
| 302 | select FSNOTIFY |
| 303 | |
| 304 | source "kernel/irq/Kconfig" |
| 305 | source "kernel/time/Kconfig" |
| 306 | |
| 307 | menu "CPU/Task time and stats accounting" |
| 308 | |
| 309 | config VIRT_CPU_ACCOUNTING |
| 310 | bool |
| 311 | |
| 312 | choice |
| 313 | prompt "Cputime accounting" |
| 314 | default TICK_CPU_ACCOUNTING if !PPC64 |
| 315 | default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
| 316 | |
| 317 | # Kind of a stub config for the pure tick based cputime accounting |
| 318 | config TICK_CPU_ACCOUNTING |
| 319 | bool "Simple tick based cputime accounting" |
| 320 | depends on !S390 && !NO_HZ_FULL |
| 321 | help |
| 322 | This is the basic tick based cputime accounting that maintains |
| 323 | statistics about user, system and idle time spent on per jiffies |
| 324 | granularity. |
| 325 | |
| 326 | If unsure, say Y. |
| 327 | |
| 328 | config VIRT_CPU_ACCOUNTING_NATIVE |
| 329 | bool "Deterministic task and CPU time accounting" |
| 330 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
| 331 | select VIRT_CPU_ACCOUNTING |
| 332 | help |
| 333 | Select this option to enable more accurate task and CPU time |
| 334 | accounting. This is done by reading a CPU counter on each |
| 335 | kernel entry and exit and on transitions within the kernel |
| 336 | between system, softirq and hardirq state, so there is a |
| 337 | small performance impact. In the case of s390 or IBM POWER > 5, |
| 338 | this also enables accounting of stolen time on logically-partitioned |
| 339 | systems. |
| 340 | |
| 341 | config VIRT_CPU_ACCOUNTING_GEN |
| 342 | bool "Full dynticks CPU time accounting" |
| 343 | depends on HAVE_CONTEXT_TRACKING |
| 344 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
| 345 | select VIRT_CPU_ACCOUNTING |
| 346 | select CONTEXT_TRACKING |
| 347 | help |
| 348 | Select this option to enable task and CPU time accounting on full |
| 349 | dynticks systems. This accounting is implemented by watching every |
| 350 | kernel-user boundaries using the context tracking subsystem. |
| 351 | The accounting is thus performed at the expense of some significant |
| 352 | overhead. |
| 353 | |
| 354 | For now this is only useful if you are working on the full |
| 355 | dynticks subsystem development. |
| 356 | |
| 357 | If unsure, say N. |
| 358 | |
| 359 | config IRQ_TIME_ACCOUNTING |
| 360 | bool "Fine granularity task level IRQ time accounting" |
| 361 | depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL |
| 362 | help |
| 363 | Select this option to enable fine granularity task irq time |
| 364 | accounting. This is done by reading a timestamp on each |
| 365 | transitions between softirq and hardirq state, so there can be a |
| 366 | small performance impact. |
| 367 | |
| 368 | If in doubt, say N here. |
| 369 | |
| 370 | endchoice |
| 371 | |
| 372 | config BSD_PROCESS_ACCT |
| 373 | bool "BSD Process Accounting" |
| 374 | help |
| 375 | If you say Y here, a user level program will be able to instruct the |
| 376 | kernel (via a special system call) to write process accounting |
| 377 | information to a file: whenever a process exits, information about |
| 378 | that process will be appended to the file by the kernel. The |
| 379 | information includes things such as creation time, owning user, |
| 380 | command name, memory usage, controlling terminal etc. (the complete |
| 381 | list is in the struct acct in <file:include/linux/acct.h>). It is |
| 382 | up to the user level program to do useful things with this |
| 383 | information. This is generally a good idea, so say Y. |
| 384 | |
| 385 | config BSD_PROCESS_ACCT_V3 |
| 386 | bool "BSD Process Accounting version 3 file format" |
| 387 | depends on BSD_PROCESS_ACCT |
| 388 | default n |
| 389 | help |
| 390 | If you say Y here, the process accounting information is written |
| 391 | in a new file format that also logs the process IDs of each |
| 392 | process and it's parent. Note that this file format is incompatible |
| 393 | with previous v0/v1/v2 file formats, so you will need updated tools |
| 394 | for processing it. A preliminary version of these tools is available |
| 395 | at <http://www.gnu.org/software/acct/>. |
| 396 | |
| 397 | config TASKSTATS |
| 398 | bool "Export task/process statistics through netlink" |
| 399 | depends on NET |
| 400 | default n |
| 401 | help |
| 402 | Export selected statistics for tasks/processes through the |
| 403 | generic netlink interface. Unlike BSD process accounting, the |
| 404 | statistics are available during the lifetime of tasks/processes as |
| 405 | responses to commands. Like BSD accounting, they are sent to user |
| 406 | space on task exit. |
| 407 | |
| 408 | Say N if unsure. |
| 409 | |
| 410 | config TASK_DELAY_ACCT |
| 411 | bool "Enable per-task delay accounting" |
| 412 | depends on TASKSTATS |
| 413 | help |
| 414 | Collect information on time spent by a task waiting for system |
| 415 | resources like cpu, synchronous block I/O completion and swapping |
| 416 | in pages. Such statistics can help in setting a task's priorities |
| 417 | relative to other tasks for cpu, io, rss limits etc. |
| 418 | |
| 419 | Say N if unsure. |
| 420 | |
| 421 | config TASK_XACCT |
| 422 | bool "Enable extended accounting over taskstats" |
| 423 | depends on TASKSTATS |
| 424 | help |
| 425 | Collect extended task accounting data and send the data |
| 426 | to userland for processing over the taskstats interface. |
| 427 | |
| 428 | Say N if unsure. |
| 429 | |
| 430 | config TASK_IO_ACCOUNTING |
| 431 | bool "Enable per-task storage I/O accounting" |
| 432 | depends on TASK_XACCT |
| 433 | help |
| 434 | Collect information on the number of bytes of storage I/O which this |
| 435 | task has caused. |
| 436 | |
| 437 | Say N if unsure. |
| 438 | |
| 439 | endmenu # "CPU/Task time and stats accounting" |
| 440 | |
| 441 | menu "RCU Subsystem" |
| 442 | |
| 443 | choice |
| 444 | prompt "RCU Implementation" |
| 445 | default TREE_RCU |
| 446 | |
| 447 | config TREE_RCU |
| 448 | bool "Tree-based hierarchical RCU" |
| 449 | depends on !PREEMPT && SMP |
| 450 | select IRQ_WORK |
| 451 | help |
| 452 | This option selects the RCU implementation that is |
| 453 | designed for very large SMP system with hundreds or |
| 454 | thousands of CPUs. It also scales down nicely to |
| 455 | smaller systems. |
| 456 | |
| 457 | config TREE_PREEMPT_RCU |
| 458 | bool "Preemptible tree-based hierarchical RCU" |
| 459 | depends on PREEMPT |
| 460 | select IRQ_WORK |
| 461 | help |
| 462 | This option selects the RCU implementation that is |
| 463 | designed for very large SMP systems with hundreds or |
| 464 | thousands of CPUs, but for which real-time response |
| 465 | is also required. It also scales down nicely to |
| 466 | smaller systems. |
| 467 | |
| 468 | Select this option if you are unsure. |
| 469 | |
| 470 | config TINY_RCU |
| 471 | bool "UP-only small-memory-footprint RCU" |
| 472 | depends on !PREEMPT && !SMP |
| 473 | help |
| 474 | This option selects the RCU implementation that is |
| 475 | designed for UP systems from which real-time response |
| 476 | is not required. This option greatly reduces the |
| 477 | memory footprint of RCU. |
| 478 | |
| 479 | endchoice |
| 480 | |
| 481 | config PREEMPT_RCU |
| 482 | def_bool TREE_PREEMPT_RCU |
| 483 | help |
| 484 | This option enables preemptible-RCU code that is common between |
| 485 | the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. |
| 486 | |
| 487 | config RCU_STALL_COMMON |
| 488 | def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE ) |
| 489 | help |
| 490 | This option enables RCU CPU stall code that is common between |
| 491 | the TINY and TREE variants of RCU. The purpose is to allow |
| 492 | the tiny variants to disable RCU CPU stall warnings, while |
| 493 | making these warnings mandatory for the tree variants. |
| 494 | |
| 495 | config CONTEXT_TRACKING |
| 496 | bool |
| 497 | |
| 498 | config RCU_USER_QS |
| 499 | bool "Consider userspace as in RCU extended quiescent state" |
| 500 | depends on HAVE_CONTEXT_TRACKING && SMP |
| 501 | select CONTEXT_TRACKING |
| 502 | help |
| 503 | This option sets hooks on kernel / userspace boundaries and |
| 504 | puts RCU in extended quiescent state when the CPU runs in |
| 505 | userspace. It means that when a CPU runs in userspace, it is |
| 506 | excluded from the global RCU state machine and thus doesn't |
| 507 | try to keep the timer tick on for RCU. |
| 508 | |
| 509 | Unless you want to hack and help the development of the full |
| 510 | dynticks mode, you shouldn't enable this option. It also |
| 511 | adds unnecessary overhead. |
| 512 | |
| 513 | If unsure say N |
| 514 | |
| 515 | config CONTEXT_TRACKING_FORCE |
| 516 | bool "Force context tracking" |
| 517 | depends on CONTEXT_TRACKING |
| 518 | default y if !NO_HZ_FULL |
| 519 | help |
| 520 | The major pre-requirement for full dynticks to work is to |
| 521 | support the context tracking subsystem. But there are also |
| 522 | other dependencies to provide in order to make the full |
| 523 | dynticks working. |
| 524 | |
| 525 | This option stands for testing when an arch implements the |
| 526 | context tracking backend but doesn't yet fullfill all the |
| 527 | requirements to make the full dynticks feature working. |
| 528 | Without the full dynticks, there is no way to test the support |
| 529 | for context tracking and the subsystems that rely on it: RCU |
| 530 | userspace extended quiescent state and tickless cputime |
| 531 | accounting. This option copes with the absence of the full |
| 532 | dynticks subsystem by forcing the context tracking on all |
| 533 | CPUs in the system. |
| 534 | |
| 535 | Say Y only if you're working on the developpement of an |
| 536 | architecture backend for the context tracking. |
| 537 | |
| 538 | Say N otherwise, this option brings an overhead that you |
| 539 | don't want in production. |
| 540 | |
| 541 | |
| 542 | config RCU_FANOUT |
| 543 | int "Tree-based hierarchical RCU fanout value" |
| 544 | range 2 64 if 64BIT |
| 545 | range 2 32 if !64BIT |
| 546 | depends on TREE_RCU || TREE_PREEMPT_RCU |
| 547 | default 64 if 64BIT |
| 548 | default 32 if !64BIT |
| 549 | help |
| 550 | This option controls the fanout of hierarchical implementations |
| 551 | of RCU, allowing RCU to work efficiently on machines with |
| 552 | large numbers of CPUs. This value must be at least the fourth |
| 553 | root of NR_CPUS, which allows NR_CPUS to be insanely large. |
| 554 | The default value of RCU_FANOUT should be used for production |
| 555 | systems, but if you are stress-testing the RCU implementation |
| 556 | itself, small RCU_FANOUT values allow you to test large-system |
| 557 | code paths on small(er) systems. |
| 558 | |
| 559 | Select a specific number if testing RCU itself. |
| 560 | Take the default if unsure. |
| 561 | |
| 562 | config RCU_FANOUT_LEAF |
| 563 | int "Tree-based hierarchical RCU leaf-level fanout value" |
| 564 | range 2 RCU_FANOUT if 64BIT |
| 565 | range 2 RCU_FANOUT if !64BIT |
| 566 | depends on TREE_RCU || TREE_PREEMPT_RCU |
| 567 | default 16 |
| 568 | help |
| 569 | This option controls the leaf-level fanout of hierarchical |
| 570 | implementations of RCU, and allows trading off cache misses |
| 571 | against lock contention. Systems that synchronize their |
| 572 | scheduling-clock interrupts for energy-efficiency reasons will |
| 573 | want the default because the smaller leaf-level fanout keeps |
| 574 | lock contention levels acceptably low. Very large systems |
| 575 | (hundreds or thousands of CPUs) will instead want to set this |
| 576 | value to the maximum value possible in order to reduce the |
| 577 | number of cache misses incurred during RCU's grace-period |
| 578 | initialization. These systems tend to run CPU-bound, and thus |
| 579 | are not helped by synchronized interrupts, and thus tend to |
| 580 | skew them, which reduces lock contention enough that large |
| 581 | leaf-level fanouts work well. |
| 582 | |
| 583 | Select a specific number if testing RCU itself. |
| 584 | |
| 585 | Select the maximum permissible value for large systems. |
| 586 | |
| 587 | Take the default if unsure. |
| 588 | |
| 589 | config RCU_FANOUT_EXACT |
| 590 | bool "Disable tree-based hierarchical RCU auto-balancing" |
| 591 | depends on TREE_RCU || TREE_PREEMPT_RCU |
| 592 | default n |
| 593 | help |
| 594 | This option forces use of the exact RCU_FANOUT value specified, |
| 595 | regardless of imbalances in the hierarchy. This is useful for |
| 596 | testing RCU itself, and might one day be useful on systems with |
| 597 | strong NUMA behavior. |
| 598 | |
| 599 | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. |
| 600 | |
| 601 | Say N if unsure. |
| 602 | |
| 603 | config RCU_FAST_NO_HZ |
| 604 | bool "Accelerate last non-dyntick-idle CPU's grace periods" |
| 605 | depends on NO_HZ_COMMON && SMP |
| 606 | default n |
| 607 | help |
| 608 | This option permits CPUs to enter dynticks-idle state even if |
| 609 | they have RCU callbacks queued, and prevents RCU from waking |
| 610 | these CPUs up more than roughly once every four jiffies (by |
| 611 | default, you can adjust this using the rcutree.rcu_idle_gp_delay |
| 612 | parameter), thus improving energy efficiency. On the other |
| 613 | hand, this option increases the duration of RCU grace periods, |
| 614 | for example, slowing down synchronize_rcu(). |
| 615 | |
| 616 | Say Y if energy efficiency is critically important, and you |
| 617 | don't care about increased grace-period durations. |
| 618 | |
| 619 | Say N if you are unsure. |
| 620 | |
| 621 | config TREE_RCU_TRACE |
| 622 | def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) |
| 623 | select DEBUG_FS |
| 624 | help |
| 625 | This option provides tracing for the TREE_RCU and |
| 626 | TREE_PREEMPT_RCU implementations, permitting Makefile to |
| 627 | trivially select kernel/rcutree_trace.c. |
| 628 | |
| 629 | config RCU_BOOST |
| 630 | bool "Enable RCU priority boosting" |
| 631 | depends on RT_MUTEXES && PREEMPT_RCU |
| 632 | default n |
| 633 | help |
| 634 | This option boosts the priority of preempted RCU readers that |
| 635 | block the current preemptible RCU grace period for too long. |
| 636 | This option also prevents heavy loads from blocking RCU |
| 637 | callback invocation for all flavors of RCU. |
| 638 | |
| 639 | Say Y here if you are working with real-time apps or heavy loads |
| 640 | Say N here if you are unsure. |
| 641 | |
| 642 | config RCU_BOOST_PRIO |
| 643 | int "Real-time priority to boost RCU readers to" |
| 644 | range 1 99 |
| 645 | depends on RCU_BOOST |
| 646 | default 1 |
| 647 | help |
| 648 | This option specifies the real-time priority to which long-term |
| 649 | preempted RCU readers are to be boosted. If you are working |
| 650 | with a real-time application that has one or more CPU-bound |
| 651 | threads running at a real-time priority level, you should set |
| 652 | RCU_BOOST_PRIO to a priority higher then the highest-priority |
| 653 | real-time CPU-bound thread. The default RCU_BOOST_PRIO value |
| 654 | of 1 is appropriate in the common case, which is real-time |
| 655 | applications that do not have any CPU-bound threads. |
| 656 | |
| 657 | Some real-time applications might not have a single real-time |
| 658 | thread that saturates a given CPU, but instead might have |
| 659 | multiple real-time threads that, taken together, fully utilize |
| 660 | that CPU. In this case, you should set RCU_BOOST_PRIO to |
| 661 | a priority higher than the lowest-priority thread that is |
| 662 | conspiring to prevent the CPU from running any non-real-time |
| 663 | tasks. For example, if one thread at priority 10 and another |
| 664 | thread at priority 5 are between themselves fully consuming |
| 665 | the CPU time on a given CPU, then RCU_BOOST_PRIO should be |
| 666 | set to priority 6 or higher. |
| 667 | |
| 668 | Specify the real-time priority, or take the default if unsure. |
| 669 | |
| 670 | config RCU_BOOST_DELAY |
| 671 | int "Milliseconds to delay boosting after RCU grace-period start" |
| 672 | range 0 3000 |
| 673 | depends on RCU_BOOST |
| 674 | default 500 |
| 675 | help |
| 676 | This option specifies the time to wait after the beginning of |
| 677 | a given grace period before priority-boosting preempted RCU |
| 678 | readers blocking that grace period. Note that any RCU reader |
| 679 | blocking an expedited RCU grace period is boosted immediately. |
| 680 | |
| 681 | Accept the default if unsure. |
| 682 | |
| 683 | config RCU_NOCB_CPU |
| 684 | bool "Offload RCU callback processing from boot-selected CPUs" |
| 685 | depends on TREE_RCU || TREE_PREEMPT_RCU |
| 686 | default n |
| 687 | help |
| 688 | Use this option to reduce OS jitter for aggressive HPC or |
| 689 | real-time workloads. It can also be used to offload RCU |
| 690 | callback invocation to energy-efficient CPUs in battery-powered |
| 691 | asymmetric multiprocessors. |
| 692 | |
| 693 | This option offloads callback invocation from the set of |
| 694 | CPUs specified at boot time by the rcu_nocbs parameter. |
| 695 | For each such CPU, a kthread ("rcuox/N") will be created to |
| 696 | invoke callbacks, where the "N" is the CPU being offloaded, |
| 697 | and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and |
| 698 | "s" for RCU-sched. Nothing prevents this kthread from running |
| 699 | on the specified CPUs, but (1) the kthreads may be preempted |
| 700 | between each callback, and (2) affinity or cgroups can be used |
| 701 | to force the kthreads to run on whatever set of CPUs is desired. |
| 702 | |
| 703 | Say Y here if you want to help to debug reduced OS jitter. |
| 704 | Say N here if you are unsure. |
| 705 | |
| 706 | choice |
| 707 | prompt "Build-forced no-CBs CPUs" |
| 708 | default RCU_NOCB_CPU_NONE |
| 709 | help |
| 710 | This option allows no-CBs CPUs (whose RCU callbacks are invoked |
| 711 | from kthreads rather than from softirq context) to be specified |
| 712 | at build time. Additional no-CBs CPUs may be specified by |
| 713 | the rcu_nocbs= boot parameter. |
| 714 | |
| 715 | config RCU_NOCB_CPU_NONE |
| 716 | bool "No build_forced no-CBs CPUs" |
| 717 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
| 718 | help |
| 719 | This option does not force any of the CPUs to be no-CBs CPUs. |
| 720 | Only CPUs designated by the rcu_nocbs= boot parameter will be |
| 721 | no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU |
| 722 | kthreads whose names begin with "rcuo". All other CPUs will |
| 723 | invoke their own RCU callbacks in softirq context. |
| 724 | |
| 725 | Select this option if you want to choose no-CBs CPUs at |
| 726 | boot time, for example, to allow testing of different no-CBs |
| 727 | configurations without having to rebuild the kernel each time. |
| 728 | |
| 729 | config RCU_NOCB_CPU_ZERO |
| 730 | bool "CPU 0 is a build_forced no-CBs CPU" |
| 731 | depends on RCU_NOCB_CPU && !NO_HZ_FULL |
| 732 | help |
| 733 | This option forces CPU 0 to be a no-CBs CPU, so that its RCU |
| 734 | callbacks are invoked by a per-CPU kthread whose name begins |
| 735 | with "rcuo". Additional CPUs may be designated as no-CBs |
| 736 | CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs. |
| 737 | All other CPUs will invoke their own RCU callbacks in softirq |
| 738 | context. |
| 739 | |
| 740 | Select this if CPU 0 needs to be a no-CBs CPU for real-time |
| 741 | or energy-efficiency reasons, but the real reason it exists |
| 742 | is to ensure that randconfig testing covers mixed systems. |
| 743 | |
| 744 | config RCU_NOCB_CPU_ALL |
| 745 | bool "All CPUs are build_forced no-CBs CPUs" |
| 746 | depends on RCU_NOCB_CPU |
| 747 | help |
| 748 | This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= |
| 749 | boot parameter will be ignored. All CPUs' RCU callbacks will |
| 750 | be executed in the context of per-CPU rcuo kthreads created for |
| 751 | this purpose. Assuming that the kthreads whose names start with |
| 752 | "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter |
| 753 | on the remaining CPUs, but might decrease memory locality during |
| 754 | RCU-callback invocation, thus potentially degrading throughput. |
| 755 | |
| 756 | Select this if all CPUs need to be no-CBs CPUs for real-time |
| 757 | or energy-efficiency reasons. |
| 758 | |
| 759 | endchoice |
| 760 | |
| 761 | endmenu # "RCU Subsystem" |
| 762 | |
| 763 | config IKCONFIG |
| 764 | tristate "Kernel .config support" |
| 765 | ---help--- |
| 766 | This option enables the complete Linux kernel ".config" file |
| 767 | contents to be saved in the kernel. It provides documentation |
| 768 | of which kernel options are used in a running kernel or in an |
| 769 | on-disk kernel. This information can be extracted from the kernel |
| 770 | image file with the script scripts/extract-ikconfig and used as |
| 771 | input to rebuild the current kernel or to build another kernel. |
| 772 | It can also be extracted from a running kernel by reading |
| 773 | /proc/config.gz if enabled (below). |
| 774 | |
| 775 | config IKCONFIG_PROC |
| 776 | bool "Enable access to .config through /proc/config.gz" |
| 777 | depends on IKCONFIG && PROC_FS |
| 778 | ---help--- |
| 779 | This option enables access to the kernel configuration file |
| 780 | through /proc/config.gz. |
| 781 | |
| 782 | config LOG_BUF_SHIFT |
| 783 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" |
| 784 | range 12 21 |
| 785 | default 17 |
| 786 | help |
| 787 | Select kernel log buffer size as a power of 2. |
| 788 | Examples: |
| 789 | 17 => 128 KB |
| 790 | 16 => 64 KB |
| 791 | 15 => 32 KB |
| 792 | 14 => 16 KB |
| 793 | 13 => 8 KB |
| 794 | 12 => 4 KB |
| 795 | |
| 796 | # |
| 797 | # Architectures with an unreliable sched_clock() should select this: |
| 798 | # |
| 799 | config HAVE_UNSTABLE_SCHED_CLOCK |
| 800 | bool |
| 801 | |
| 802 | config GENERIC_SCHED_CLOCK |
| 803 | bool |
| 804 | |
| 805 | # |
| 806 | # For architectures that want to enable the support for NUMA-affine scheduler |
| 807 | # balancing logic: |
| 808 | # |
| 809 | config ARCH_SUPPORTS_NUMA_BALANCING |
| 810 | bool |
| 811 | |
| 812 | # |
| 813 | # For architectures that know their GCC __int128 support is sound |
| 814 | # |
| 815 | config ARCH_SUPPORTS_INT128 |
| 816 | bool |
| 817 | |
| 818 | # For architectures that (ab)use NUMA to represent different memory regions |
| 819 | # all cpu-local but of different latencies, such as SuperH. |
| 820 | # |
| 821 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 822 | bool |
| 823 | |
| 824 | # |
| 825 | # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE |
| 826 | config ARCH_WANTS_PROT_NUMA_PROT_NONE |
| 827 | bool |
| 828 | |
| 829 | config ARCH_USES_NUMA_PROT_NONE |
| 830 | bool |
| 831 | default y |
| 832 | depends on ARCH_WANTS_PROT_NUMA_PROT_NONE |
| 833 | depends on NUMA_BALANCING |
| 834 | |
| 835 | config NUMA_BALANCING_DEFAULT_ENABLED |
| 836 | bool "Automatically enable NUMA aware memory/task placement" |
| 837 | default y |
| 838 | depends on NUMA_BALANCING |
| 839 | help |
| 840 | If set, automatic NUMA balancing will be enabled if running on a NUMA |
| 841 | machine. |
| 842 | |
| 843 | config NUMA_BALANCING |
| 844 | bool "Memory placement aware NUMA scheduler" |
| 845 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
| 846 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 847 | depends on SMP && NUMA && MIGRATION |
| 848 | help |
| 849 | This option adds support for automatic NUMA aware memory/task placement. |
| 850 | The mechanism is quite primitive and is based on migrating memory when |
| 851 | it has references to the node the task is running on. |
| 852 | |
| 853 | This system will be inactive on UMA systems. |
| 854 | |
| 855 | menuconfig CGROUPS |
| 856 | boolean "Control Group support" |
| 857 | depends on EVENTFD |
| 858 | help |
| 859 | This option adds support for grouping sets of processes together, for |
| 860 | use with process control subsystems such as Cpusets, CFS, memory |
| 861 | controls or device isolation. |
| 862 | See |
| 863 | - Documentation/scheduler/sched-design-CFS.txt (CFS) |
| 864 | - Documentation/cgroups/ (features for grouping, isolation |
| 865 | and resource control) |
| 866 | |
| 867 | Say N if unsure. |
| 868 | |
| 869 | if CGROUPS |
| 870 | |
| 871 | config CGROUP_DEBUG |
| 872 | bool "Example debug cgroup subsystem" |
| 873 | default n |
| 874 | help |
| 875 | This option enables a simple cgroup subsystem that |
| 876 | exports useful debugging information about the cgroups |
| 877 | framework. |
| 878 | |
| 879 | Say N if unsure. |
| 880 | |
| 881 | config CGROUP_FREEZER |
| 882 | bool "Freezer cgroup subsystem" |
| 883 | help |
| 884 | Provides a way to freeze and unfreeze all tasks in a |
| 885 | cgroup. |
| 886 | |
| 887 | config CGROUP_DEVICE |
| 888 | bool "Device controller for cgroups" |
| 889 | help |
| 890 | Provides a cgroup implementing whitelists for devices which |
| 891 | a process in the cgroup can mknod or open. |
| 892 | |
| 893 | config CPUSETS |
| 894 | bool "Cpuset support" |
| 895 | help |
| 896 | This option will let you create and manage CPUSETs which |
| 897 | allow dynamically partitioning a system into sets of CPUs and |
| 898 | Memory Nodes and assigning tasks to run only within those sets. |
| 899 | This is primarily useful on large SMP or NUMA systems. |
| 900 | |
| 901 | Say N if unsure. |
| 902 | |
| 903 | config PROC_PID_CPUSET |
| 904 | bool "Include legacy /proc/<pid>/cpuset file" |
| 905 | depends on CPUSETS |
| 906 | default y |
| 907 | |
| 908 | config CGROUP_CPUACCT |
| 909 | bool "Simple CPU accounting cgroup subsystem" |
| 910 | help |
| 911 | Provides a simple Resource Controller for monitoring the |
| 912 | total CPU consumed by the tasks in a cgroup. |
| 913 | |
| 914 | config RESOURCE_COUNTERS |
| 915 | bool "Resource counters" |
| 916 | help |
| 917 | This option enables controller independent resource accounting |
| 918 | infrastructure that works with cgroups. |
| 919 | |
| 920 | config MEMCG |
| 921 | bool "Memory Resource Controller for Control Groups" |
| 922 | depends on RESOURCE_COUNTERS |
| 923 | select MM_OWNER |
| 924 | help |
| 925 | Provides a memory resource controller that manages both anonymous |
| 926 | memory and page cache. (See Documentation/cgroups/memory.txt) |
| 927 | |
| 928 | Note that setting this option increases fixed memory overhead |
| 929 | associated with each page of memory in the system. By this, |
| 930 | 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory |
| 931 | usage tracking struct at boot. Total amount of this is printed out |
| 932 | at boot. |
| 933 | |
| 934 | Only enable when you're ok with these trade offs and really |
| 935 | sure you need the memory resource controller. Even when you enable |
| 936 | this, you can set "cgroup_disable=memory" at your boot option to |
| 937 | disable memory resource controller and you can avoid overheads. |
| 938 | (and lose benefits of memory resource controller) |
| 939 | |
| 940 | This config option also selects MM_OWNER config option, which |
| 941 | could in turn add some fork/exit overhead. |
| 942 | |
| 943 | config MEMCG_SWAP |
| 944 | bool "Memory Resource Controller Swap Extension" |
| 945 | depends on MEMCG && SWAP |
| 946 | help |
| 947 | Add swap management feature to memory resource controller. When you |
| 948 | enable this, you can limit mem+swap usage per cgroup. In other words, |
| 949 | when you disable this, memory resource controller has no cares to |
| 950 | usage of swap...a process can exhaust all of the swap. This extension |
| 951 | is useful when you want to avoid exhaustion swap but this itself |
| 952 | adds more overheads and consumes memory for remembering information. |
| 953 | Especially if you use 32bit system or small memory system, please |
| 954 | be careful about enabling this. When memory resource controller |
| 955 | is disabled by boot option, this will be automatically disabled and |
| 956 | there will be no overhead from this. Even when you set this config=y, |
| 957 | if boot option "swapaccount=0" is set, swap will not be accounted. |
| 958 | Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page |
| 959 | size is 4096bytes, 512k per 1Gbytes of swap. |
| 960 | config MEMCG_SWAP_ENABLED |
| 961 | bool "Memory Resource Controller Swap Extension enabled by default" |
| 962 | depends on MEMCG_SWAP |
| 963 | default y |
| 964 | help |
| 965 | Memory Resource Controller Swap Extension comes with its price in |
| 966 | a bigger memory consumption. General purpose distribution kernels |
| 967 | which want to enable the feature but keep it disabled by default |
| 968 | and let the user enable it by swapaccount=1 boot command line |
| 969 | parameter should have this option unselected. |
| 970 | For those who want to have the feature enabled by default should |
| 971 | select this option (if, for some reason, they need to disable it |
| 972 | then swapaccount=0 does the trick). |
| 973 | config MEMCG_KMEM |
| 974 | bool "Memory Resource Controller Kernel Memory accounting" |
| 975 | depends on MEMCG |
| 976 | depends on SLUB || SLAB |
| 977 | help |
| 978 | The Kernel Memory extension for Memory Resource Controller can limit |
| 979 | the amount of memory used by kernel objects in the system. Those are |
| 980 | fundamentally different from the entities handled by the standard |
| 981 | Memory Controller, which are page-based, and can be swapped. Users of |
| 982 | the kmem extension can use it to guarantee that no group of processes |
| 983 | will ever exhaust kernel resources alone. |
| 984 | |
| 985 | config CGROUP_HUGETLB |
| 986 | bool "HugeTLB Resource Controller for Control Groups" |
| 987 | depends on RESOURCE_COUNTERS && HUGETLB_PAGE |
| 988 | default n |
| 989 | help |
| 990 | Provides a cgroup Resource Controller for HugeTLB pages. |
| 991 | When you enable this, you can put a per cgroup limit on HugeTLB usage. |
| 992 | The limit is enforced during page fault. Since HugeTLB doesn't |
| 993 | support page reclaim, enforcing the limit at page fault time implies |
| 994 | that, the application will get SIGBUS signal if it tries to access |
| 995 | HugeTLB pages beyond its limit. This requires the application to know |
| 996 | beforehand how much HugeTLB pages it would require for its use. The |
| 997 | control group is tracked in the third page lru pointer. This means |
| 998 | that we cannot use the controller with huge page less than 3 pages. |
| 999 | |
| 1000 | config CGROUP_PERF |
| 1001 | bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" |
| 1002 | depends on PERF_EVENTS && CGROUPS |
| 1003 | help |
| 1004 | This option extends the per-cpu mode to restrict monitoring to |
| 1005 | threads which belong to the cgroup specified and run on the |
| 1006 | designated cpu. |
| 1007 | |
| 1008 | Say N if unsure. |
| 1009 | |
| 1010 | menuconfig CGROUP_SCHED |
| 1011 | bool "Group CPU scheduler" |
| 1012 | default n |
| 1013 | help |
| 1014 | This feature lets CPU scheduler recognize task groups and control CPU |
| 1015 | bandwidth allocation to such task groups. It uses cgroups to group |
| 1016 | tasks. |
| 1017 | |
| 1018 | if CGROUP_SCHED |
| 1019 | config FAIR_GROUP_SCHED |
| 1020 | bool "Group scheduling for SCHED_OTHER" |
| 1021 | depends on CGROUP_SCHED |
| 1022 | default CGROUP_SCHED |
| 1023 | |
| 1024 | config CFS_BANDWIDTH |
| 1025 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" |
| 1026 | depends on FAIR_GROUP_SCHED |
| 1027 | default n |
| 1028 | help |
| 1029 | This option allows users to define CPU bandwidth rates (limits) for |
| 1030 | tasks running within the fair group scheduler. Groups with no limit |
| 1031 | set are considered to be unconstrained and will run with no |
| 1032 | restriction. |
| 1033 | See tip/Documentation/scheduler/sched-bwc.txt for more information. |
| 1034 | |
| 1035 | config RT_GROUP_SCHED |
| 1036 | bool "Group scheduling for SCHED_RR/FIFO" |
| 1037 | depends on CGROUP_SCHED |
| 1038 | default n |
| 1039 | help |
| 1040 | This feature lets you explicitly allocate real CPU bandwidth |
| 1041 | to task groups. If enabled, it will also make it impossible to |
| 1042 | schedule realtime tasks for non-root users until you allocate |
| 1043 | realtime bandwidth for them. |
| 1044 | See Documentation/scheduler/sched-rt-group.txt for more information. |
| 1045 | |
| 1046 | endif #CGROUP_SCHED |
| 1047 | |
| 1048 | config BLK_CGROUP |
| 1049 | bool "Block IO controller" |
| 1050 | depends on BLOCK |
| 1051 | default n |
| 1052 | ---help--- |
| 1053 | Generic block IO controller cgroup interface. This is the common |
| 1054 | cgroup interface which should be used by various IO controlling |
| 1055 | policies. |
| 1056 | |
| 1057 | Currently, CFQ IO scheduler uses it to recognize task groups and |
| 1058 | control disk bandwidth allocation (proportional time slice allocation) |
| 1059 | to such task groups. It is also used by bio throttling logic in |
| 1060 | block layer to implement upper limit in IO rates on a device. |
| 1061 | |
| 1062 | This option only enables generic Block IO controller infrastructure. |
| 1063 | One needs to also enable actual IO controlling logic/policy. For |
| 1064 | enabling proportional weight division of disk bandwidth in CFQ, set |
| 1065 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set |
| 1066 | CONFIG_BLK_DEV_THROTTLING=y. |
| 1067 | |
| 1068 | See Documentation/cgroups/blkio-controller.txt for more information. |
| 1069 | |
| 1070 | config DEBUG_BLK_CGROUP |
| 1071 | bool "Enable Block IO controller debugging" |
| 1072 | depends on BLK_CGROUP |
| 1073 | default n |
| 1074 | ---help--- |
| 1075 | Enable some debugging help. Currently it exports additional stat |
| 1076 | files in a cgroup which can be useful for debugging. |
| 1077 | |
| 1078 | endif # CGROUPS |
| 1079 | |
| 1080 | config CHECKPOINT_RESTORE |
| 1081 | bool "Checkpoint/restore support" if EXPERT |
| 1082 | default n |
| 1083 | help |
| 1084 | Enables additional kernel features in a sake of checkpoint/restore. |
| 1085 | In particular it adds auxiliary prctl codes to setup process text, |
| 1086 | data and heap segment sizes, and a few additional /proc filesystem |
| 1087 | entries. |
| 1088 | |
| 1089 | If unsure, say N here. |
| 1090 | |
| 1091 | menuconfig NAMESPACES |
| 1092 | bool "Namespaces support" if EXPERT |
| 1093 | default !EXPERT |
| 1094 | help |
| 1095 | Provides the way to make tasks work with different objects using |
| 1096 | the same id. For example same IPC id may refer to different objects |
| 1097 | or same user id or pid may refer to different tasks when used in |
| 1098 | different namespaces. |
| 1099 | |
| 1100 | if NAMESPACES |
| 1101 | |
| 1102 | config UTS_NS |
| 1103 | bool "UTS namespace" |
| 1104 | default y |
| 1105 | help |
| 1106 | In this namespace tasks see different info provided with the |
| 1107 | uname() system call |
| 1108 | |
| 1109 | config IPC_NS |
| 1110 | bool "IPC namespace" |
| 1111 | depends on (SYSVIPC || POSIX_MQUEUE) |
| 1112 | default y |
| 1113 | help |
| 1114 | In this namespace tasks work with IPC ids which correspond to |
| 1115 | different IPC objects in different namespaces. |
| 1116 | |
| 1117 | config USER_NS |
| 1118 | bool "User namespace" |
| 1119 | select UIDGID_STRICT_TYPE_CHECKS |
| 1120 | |
| 1121 | default n |
| 1122 | help |
| 1123 | This allows containers, i.e. vservers, to use user namespaces |
| 1124 | to provide different user info for different servers. |
| 1125 | |
| 1126 | When user namespaces are enabled in the kernel it is |
| 1127 | recommended that the MEMCG and MEMCG_KMEM options also be |
| 1128 | enabled and that user-space use the memory control groups to |
| 1129 | limit the amount of memory a memory unprivileged users can |
| 1130 | use. |
| 1131 | |
| 1132 | If unsure, say N. |
| 1133 | |
| 1134 | config PID_NS |
| 1135 | bool "PID Namespaces" |
| 1136 | default y |
| 1137 | help |
| 1138 | Support process id namespaces. This allows having multiple |
| 1139 | processes with the same pid as long as they are in different |
| 1140 | pid namespaces. This is a building block of containers. |
| 1141 | |
| 1142 | config NET_NS |
| 1143 | bool "Network namespace" |
| 1144 | depends on NET |
| 1145 | default y |
| 1146 | help |
| 1147 | Allow user space to create what appear to be multiple instances |
| 1148 | of the network stack. |
| 1149 | |
| 1150 | endif # NAMESPACES |
| 1151 | |
| 1152 | config UIDGID_STRICT_TYPE_CHECKS |
| 1153 | bool "Require conversions between uid/gids and their internal representation" |
| 1154 | default n |
| 1155 | help |
| 1156 | While the nececessary conversions are being added to all subsystems this option allows |
| 1157 | the code to continue to build for unconverted subsystems. |
| 1158 | |
| 1159 | Say Y here if you want the strict type checking enabled |
| 1160 | |
| 1161 | config SCHED_AUTOGROUP |
| 1162 | bool "Automatic process group scheduling" |
| 1163 | select EVENTFD |
| 1164 | select CGROUPS |
| 1165 | select CGROUP_SCHED |
| 1166 | select FAIR_GROUP_SCHED |
| 1167 | help |
| 1168 | This option optimizes the scheduler for common desktop workloads by |
| 1169 | automatically creating and populating task groups. This separation |
| 1170 | of workloads isolates aggressive CPU burners (like build jobs) from |
| 1171 | desktop applications. Task group autogeneration is currently based |
| 1172 | upon task session. |
| 1173 | |
| 1174 | config MM_OWNER |
| 1175 | bool |
| 1176 | |
| 1177 | config SYSFS_DEPRECATED |
| 1178 | bool "Enable deprecated sysfs features to support old userspace tools" |
| 1179 | depends on SYSFS |
| 1180 | default n |
| 1181 | help |
| 1182 | This option adds code that switches the layout of the "block" class |
| 1183 | devices, to not show up in /sys/class/block/, but only in |
| 1184 | /sys/block/. |
| 1185 | |
| 1186 | This switch is only active when the sysfs.deprecated=1 boot option is |
| 1187 | passed or the SYSFS_DEPRECATED_V2 option is set. |
| 1188 | |
| 1189 | This option allows new kernels to run on old distributions and tools, |
| 1190 | which might get confused by /sys/class/block/. Since 2007/2008 all |
| 1191 | major distributions and tools handle this just fine. |
| 1192 | |
| 1193 | Recent distributions and userspace tools after 2009/2010 depend on |
| 1194 | the existence of /sys/class/block/, and will not work with this |
| 1195 | option enabled. |
| 1196 | |
| 1197 | Only if you are using a new kernel on an old distribution, you might |
| 1198 | need to say Y here. |
| 1199 | |
| 1200 | config SYSFS_DEPRECATED_V2 |
| 1201 | bool "Enable deprecated sysfs features by default" |
| 1202 | default n |
| 1203 | depends on SYSFS |
| 1204 | depends on SYSFS_DEPRECATED |
| 1205 | help |
| 1206 | Enable deprecated sysfs by default. |
| 1207 | |
| 1208 | See the CONFIG_SYSFS_DEPRECATED option for more details about this |
| 1209 | option. |
| 1210 | |
| 1211 | Only if you are using a new kernel on an old distribution, you might |
| 1212 | need to say Y here. Even then, odds are you would not need it |
| 1213 | enabled, you can always pass the boot option if absolutely necessary. |
| 1214 | |
| 1215 | config RELAY |
| 1216 | bool "Kernel->user space relay support (formerly relayfs)" |
| 1217 | help |
| 1218 | This option enables support for relay interface support in |
| 1219 | certain file systems (such as debugfs). |
| 1220 | It is designed to provide an efficient mechanism for tools and |
| 1221 | facilities to relay large amounts of data from kernel space to |
| 1222 | user space. |
| 1223 | |
| 1224 | If unsure, say N. |
| 1225 | |
| 1226 | config BLK_DEV_INITRD |
| 1227 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" |
| 1228 | depends on BROKEN || !FRV |
| 1229 | help |
| 1230 | The initial RAM filesystem is a ramfs which is loaded by the |
| 1231 | boot loader (loadlin or lilo) and that is mounted as root |
| 1232 | before the normal boot procedure. It is typically used to |
| 1233 | load modules needed to mount the "real" root file system, |
| 1234 | etc. See <file:Documentation/initrd.txt> for details. |
| 1235 | |
| 1236 | If RAM disk support (BLK_DEV_RAM) is also included, this |
| 1237 | also enables initial RAM disk (initrd) support and adds |
| 1238 | 15 Kbytes (more on some other architectures) to the kernel size. |
| 1239 | |
| 1240 | If unsure say Y. |
| 1241 | |
| 1242 | if BLK_DEV_INITRD |
| 1243 | |
| 1244 | source "usr/Kconfig" |
| 1245 | |
| 1246 | endif |
| 1247 | |
| 1248 | config CC_OPTIMIZE_FOR_SIZE |
| 1249 | bool "Optimize for size" |
| 1250 | help |
| 1251 | Enabling this option will pass "-Os" instead of "-O2" to gcc |
| 1252 | resulting in a smaller kernel. |
| 1253 | |
| 1254 | If unsure, say N. |
| 1255 | |
| 1256 | config SYSCTL |
| 1257 | bool |
| 1258 | |
| 1259 | config ANON_INODES |
| 1260 | bool |
| 1261 | |
| 1262 | config HAVE_UID16 |
| 1263 | bool |
| 1264 | |
| 1265 | config SYSCTL_EXCEPTION_TRACE |
| 1266 | bool |
| 1267 | help |
| 1268 | Enable support for /proc/sys/debug/exception-trace. |
| 1269 | |
| 1270 | config SYSCTL_ARCH_UNALIGN_NO_WARN |
| 1271 | bool |
| 1272 | help |
| 1273 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap |
| 1274 | Allows arch to define/use @no_unaligned_warning to possibly warn |
| 1275 | about unaligned access emulation going on under the hood. |
| 1276 | |
| 1277 | config SYSCTL_ARCH_UNALIGN_ALLOW |
| 1278 | bool |
| 1279 | help |
| 1280 | Enable support for /proc/sys/kernel/unaligned-trap |
| 1281 | Allows arches to define/use @unaligned_enabled to runtime toggle |
| 1282 | the unaligned access emulation. |
| 1283 | see arch/parisc/kernel/unaligned.c for reference |
| 1284 | |
| 1285 | config HAVE_PCSPKR_PLATFORM |
| 1286 | bool |
| 1287 | |
| 1288 | menuconfig EXPERT |
| 1289 | bool "Configure standard kernel features (expert users)" |
| 1290 | # Unhide debug options, to make the on-by-default options visible |
| 1291 | select DEBUG_KERNEL |
| 1292 | help |
| 1293 | This option allows certain base kernel options and settings |
| 1294 | to be disabled or tweaked. This is for specialized |
| 1295 | environments which can tolerate a "non-standard" kernel. |
| 1296 | Only use this if you really know what you are doing. |
| 1297 | |
| 1298 | config UID16 |
| 1299 | bool "Enable 16-bit UID system calls" if EXPERT |
| 1300 | depends on HAVE_UID16 |
| 1301 | default y |
| 1302 | help |
| 1303 | This enables the legacy 16-bit UID syscall wrappers. |
| 1304 | |
| 1305 | config SYSCTL_SYSCALL |
| 1306 | bool "Sysctl syscall support" if EXPERT |
| 1307 | depends on PROC_SYSCTL |
| 1308 | default n |
| 1309 | select SYSCTL |
| 1310 | ---help--- |
| 1311 | sys_sysctl uses binary paths that have been found challenging |
| 1312 | to properly maintain and use. The interface in /proc/sys |
| 1313 | using paths with ascii names is now the primary path to this |
| 1314 | information. |
| 1315 | |
| 1316 | Almost nothing using the binary sysctl interface so if you are |
| 1317 | trying to save some space it is probably safe to disable this, |
| 1318 | making your kernel marginally smaller. |
| 1319 | |
| 1320 | If unsure say N here. |
| 1321 | |
| 1322 | config KALLSYMS |
| 1323 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
| 1324 | default y |
| 1325 | help |
| 1326 | Say Y here to let the kernel print out symbolic crash information and |
| 1327 | symbolic stack backtraces. This increases the size of the kernel |
| 1328 | somewhat, as all symbols have to be loaded into the kernel image. |
| 1329 | |
| 1330 | config KALLSYMS_ALL |
| 1331 | bool "Include all symbols in kallsyms" |
| 1332 | depends on DEBUG_KERNEL && KALLSYMS |
| 1333 | help |
| 1334 | Normally kallsyms only contains the symbols of functions for nicer |
| 1335 | OOPS messages and backtraces (i.e., symbols from the text and inittext |
| 1336 | sections). This is sufficient for most cases. And only in very rare |
| 1337 | cases (e.g., when a debugger is used) all symbols are required (e.g., |
| 1338 | names of variables from the data sections, etc). |
| 1339 | |
| 1340 | This option makes sure that all symbols are loaded into the kernel |
| 1341 | image (i.e., symbols from all sections) in cost of increased kernel |
| 1342 | size (depending on the kernel configuration, it may be 300KiB or |
| 1343 | something like this). |
| 1344 | |
| 1345 | Say N unless you really need all symbols. |
| 1346 | |
| 1347 | config PRINTK |
| 1348 | default y |
| 1349 | bool "Enable support for printk" if EXPERT |
| 1350 | select IRQ_WORK |
| 1351 | help |
| 1352 | This option enables normal printk support. Removing it |
| 1353 | eliminates most of the message strings from the kernel image |
| 1354 | and makes the kernel more or less silent. As this makes it |
| 1355 | very difficult to diagnose system problems, saying N here is |
| 1356 | strongly discouraged. |
| 1357 | |
| 1358 | config BUG |
| 1359 | bool "BUG() support" if EXPERT |
| 1360 | default y |
| 1361 | help |
| 1362 | Disabling this option eliminates support for BUG and WARN, reducing |
| 1363 | the size of your kernel image and potentially quietly ignoring |
| 1364 | numerous fatal conditions. You should only consider disabling this |
| 1365 | option for embedded systems with no facilities for reporting errors. |
| 1366 | Just say Y. |
| 1367 | |
| 1368 | config ELF_CORE |
| 1369 | depends on COREDUMP |
| 1370 | default y |
| 1371 | bool "Enable ELF core dumps" if EXPERT |
| 1372 | help |
| 1373 | Enable support for generating core dumps. Disabling saves about 4k. |
| 1374 | |
| 1375 | |
| 1376 | config PCSPKR_PLATFORM |
| 1377 | bool "Enable PC-Speaker support" if EXPERT |
| 1378 | depends on HAVE_PCSPKR_PLATFORM |
| 1379 | select I8253_LOCK |
| 1380 | default y |
| 1381 | help |
| 1382 | This option allows to disable the internal PC-Speaker |
| 1383 | support, saving some memory. |
| 1384 | |
| 1385 | config BASE_FULL |
| 1386 | default y |
| 1387 | bool "Enable full-sized data structures for core" if EXPERT |
| 1388 | help |
| 1389 | Disabling this option reduces the size of miscellaneous core |
| 1390 | kernel data structures. This saves memory on small machines, |
| 1391 | but may reduce performance. |
| 1392 | |
| 1393 | config FUTEX |
| 1394 | bool "Enable futex support" if EXPERT |
| 1395 | default y |
| 1396 | select RT_MUTEXES |
| 1397 | help |
| 1398 | Disabling this option will cause the kernel to be built without |
| 1399 | support for "fast userspace mutexes". The resulting kernel may not |
| 1400 | run glibc-based applications correctly. |
| 1401 | |
| 1402 | config EPOLL |
| 1403 | bool "Enable eventpoll support" if EXPERT |
| 1404 | default y |
| 1405 | select ANON_INODES |
| 1406 | help |
| 1407 | Disabling this option will cause the kernel to be built without |
| 1408 | support for epoll family of system calls. |
| 1409 | |
| 1410 | config SIGNALFD |
| 1411 | bool "Enable signalfd() system call" if EXPERT |
| 1412 | select ANON_INODES |
| 1413 | default y |
| 1414 | help |
| 1415 | Enable the signalfd() system call that allows to receive signals |
| 1416 | on a file descriptor. |
| 1417 | |
| 1418 | If unsure, say Y. |
| 1419 | |
| 1420 | config TIMERFD |
| 1421 | bool "Enable timerfd() system call" if EXPERT |
| 1422 | select ANON_INODES |
| 1423 | default y |
| 1424 | help |
| 1425 | Enable the timerfd() system call that allows to receive timer |
| 1426 | events on a file descriptor. |
| 1427 | |
| 1428 | If unsure, say Y. |
| 1429 | |
| 1430 | config EVENTFD |
| 1431 | bool "Enable eventfd() system call" if EXPERT |
| 1432 | select ANON_INODES |
| 1433 | default y |
| 1434 | help |
| 1435 | Enable the eventfd() system call that allows to receive both |
| 1436 | kernel notification (ie. KAIO) or userspace notifications. |
| 1437 | |
| 1438 | If unsure, say Y. |
| 1439 | |
| 1440 | config SHMEM |
| 1441 | bool "Use full shmem filesystem" if EXPERT |
| 1442 | default y |
| 1443 | depends on MMU |
| 1444 | help |
| 1445 | The shmem is an internal filesystem used to manage shared memory. |
| 1446 | It is backed by swap and manages resource limits. It is also exported |
| 1447 | to userspace as tmpfs if TMPFS is enabled. Disabling this |
| 1448 | option replaces shmem and tmpfs with the much simpler ramfs code, |
| 1449 | which may be appropriate on small systems without swap. |
| 1450 | |
| 1451 | config AIO |
| 1452 | bool "Enable AIO support" if EXPERT |
| 1453 | default y |
| 1454 | help |
| 1455 | This option enables POSIX asynchronous I/O which may by used |
| 1456 | by some high performance threaded applications. Disabling |
| 1457 | this option saves about 7k. |
| 1458 | |
| 1459 | config PCI_QUIRKS |
| 1460 | default y |
| 1461 | bool "Enable PCI quirk workarounds" if EXPERT |
| 1462 | depends on PCI |
| 1463 | help |
| 1464 | This enables workarounds for various PCI chipset |
| 1465 | bugs/quirks. Disable this only if your target machine is |
| 1466 | unaffected by PCI quirks. |
| 1467 | |
| 1468 | config EMBEDDED |
| 1469 | bool "Embedded system" |
| 1470 | select EXPERT |
| 1471 | help |
| 1472 | This option should be enabled if compiling the kernel for |
| 1473 | an embedded system so certain expert options are available |
| 1474 | for configuration. |
| 1475 | |
| 1476 | config HAVE_PERF_EVENTS |
| 1477 | bool |
| 1478 | help |
| 1479 | See tools/perf/design.txt for details. |
| 1480 | |
| 1481 | config PERF_USE_VMALLOC |
| 1482 | bool |
| 1483 | help |
| 1484 | See tools/perf/design.txt for details |
| 1485 | |
| 1486 | menu "Kernel Performance Events And Counters" |
| 1487 | |
| 1488 | config PERF_EVENTS |
| 1489 | bool "Kernel performance events and counters" |
| 1490 | default y if PROFILING |
| 1491 | depends on HAVE_PERF_EVENTS |
| 1492 | select ANON_INODES |
| 1493 | select IRQ_WORK |
| 1494 | help |
| 1495 | Enable kernel support for various performance events provided |
| 1496 | by software and hardware. |
| 1497 | |
| 1498 | Software events are supported either built-in or via the |
| 1499 | use of generic tracepoints. |
| 1500 | |
| 1501 | Most modern CPUs support performance events via performance |
| 1502 | counter registers. These registers count the number of certain |
| 1503 | types of hw events: such as instructions executed, cachemisses |
| 1504 | suffered, or branches mis-predicted - without slowing down the |
| 1505 | kernel or applications. These registers can also trigger interrupts |
| 1506 | when a threshold number of events have passed - and can thus be |
| 1507 | used to profile the code that runs on that CPU. |
| 1508 | |
| 1509 | The Linux Performance Event subsystem provides an abstraction of |
| 1510 | these software and hardware event capabilities, available via a |
| 1511 | system call and used by the "perf" utility in tools/perf/. It |
| 1512 | provides per task and per CPU counters, and it provides event |
| 1513 | capabilities on top of those. |
| 1514 | |
| 1515 | Say Y if unsure. |
| 1516 | |
| 1517 | config DEBUG_PERF_USE_VMALLOC |
| 1518 | default n |
| 1519 | bool "Debug: use vmalloc to back perf mmap() buffers" |
| 1520 | depends on PERF_EVENTS && DEBUG_KERNEL |
| 1521 | select PERF_USE_VMALLOC |
| 1522 | help |
| 1523 | Use vmalloc memory to back perf mmap() buffers. |
| 1524 | |
| 1525 | Mostly useful for debugging the vmalloc code on platforms |
| 1526 | that don't require it. |
| 1527 | |
| 1528 | Say N if unsure. |
| 1529 | |
| 1530 | endmenu |
| 1531 | |
| 1532 | config VM_EVENT_COUNTERS |
| 1533 | default y |
| 1534 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
| 1535 | help |
| 1536 | VM event counters are needed for event counts to be shown. |
| 1537 | This option allows the disabling of the VM event counters |
| 1538 | on EXPERT systems. /proc/vmstat will only show page counts |
| 1539 | if VM event counters are disabled. |
| 1540 | |
| 1541 | config SLUB_DEBUG |
| 1542 | default y |
| 1543 | bool "Enable SLUB debugging support" if EXPERT |
| 1544 | depends on SLUB && SYSFS |
| 1545 | help |
| 1546 | SLUB has extensive debug support features. Disabling these can |
| 1547 | result in significant savings in code size. This also disables |
| 1548 | SLUB sysfs support. /sys/slab will not exist and there will be |
| 1549 | no support for cache validation etc. |
| 1550 | |
| 1551 | config COMPAT_BRK |
| 1552 | bool "Disable heap randomization" |
| 1553 | default y |
| 1554 | help |
| 1555 | Randomizing heap placement makes heap exploits harder, but it |
| 1556 | also breaks ancient binaries (including anything libc5 based). |
| 1557 | This option changes the bootup default to heap randomization |
| 1558 | disabled, and can be overridden at runtime by setting |
| 1559 | /proc/sys/kernel/randomize_va_space to 2. |
| 1560 | |
| 1561 | On non-ancient distros (post-2000 ones) N is usually a safe choice. |
| 1562 | |
| 1563 | choice |
| 1564 | prompt "Choose SLAB allocator" |
| 1565 | default SLUB |
| 1566 | help |
| 1567 | This option allows to select a slab allocator. |
| 1568 | |
| 1569 | config SLAB |
| 1570 | bool "SLAB" |
| 1571 | help |
| 1572 | The regular slab allocator that is established and known to work |
| 1573 | well in all environments. It organizes cache hot objects in |
| 1574 | per cpu and per node queues. |
| 1575 | |
| 1576 | config SLUB |
| 1577 | bool "SLUB (Unqueued Allocator)" |
| 1578 | help |
| 1579 | SLUB is a slab allocator that minimizes cache line usage |
| 1580 | instead of managing queues of cached objects (SLAB approach). |
| 1581 | Per cpu caching is realized using slabs of objects instead |
| 1582 | of queues of objects. SLUB can use memory efficiently |
| 1583 | and has enhanced diagnostics. SLUB is the default choice for |
| 1584 | a slab allocator. |
| 1585 | |
| 1586 | config SLOB |
| 1587 | depends on EXPERT |
| 1588 | bool "SLOB (Simple Allocator)" |
| 1589 | help |
| 1590 | SLOB replaces the stock allocator with a drastically simpler |
| 1591 | allocator. SLOB is generally more space efficient but |
| 1592 | does not perform as well on large systems. |
| 1593 | |
| 1594 | endchoice |
| 1595 | |
| 1596 | config SLUB_CPU_PARTIAL |
| 1597 | default y |
| 1598 | depends on SLUB && SMP |
| 1599 | bool "SLUB per cpu partial cache" |
| 1600 | help |
| 1601 | Per cpu partial caches accellerate objects allocation and freeing |
| 1602 | that is local to a processor at the price of more indeterminism |
| 1603 | in the latency of the free. On overflow these caches will be cleared |
| 1604 | which requires the taking of locks that may cause latency spikes. |
| 1605 | Typically one would choose no for a realtime system. |
| 1606 | |
| 1607 | config MMAP_ALLOW_UNINITIALIZED |
| 1608 | bool "Allow mmapped anonymous memory to be uninitialized" |
| 1609 | depends on EXPERT && !MMU |
| 1610 | default n |
| 1611 | help |
| 1612 | Normally, and according to the Linux spec, anonymous memory obtained |
| 1613 | from mmap() has it's contents cleared before it is passed to |
| 1614 | userspace. Enabling this config option allows you to request that |
| 1615 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus |
| 1616 | providing a huge performance boost. If this option is not enabled, |
| 1617 | then the flag will be ignored. |
| 1618 | |
| 1619 | This is taken advantage of by uClibc's malloc(), and also by |
| 1620 | ELF-FDPIC binfmt's brk and stack allocator. |
| 1621 | |
| 1622 | Because of the obvious security issues, this option should only be |
| 1623 | enabled on embedded devices where you control what is run in |
| 1624 | userspace. Since that isn't generally a problem on no-MMU systems, |
| 1625 | it is normally safe to say Y here. |
| 1626 | |
| 1627 | See Documentation/nommu-mmap.txt for more information. |
| 1628 | |
| 1629 | config PROFILING |
| 1630 | bool "Profiling support" |
| 1631 | help |
| 1632 | Say Y here to enable the extended profiling support mechanisms used |
| 1633 | by profilers such as OProfile. |
| 1634 | |
| 1635 | # |
| 1636 | # Place an empty function call at each tracepoint site. Can be |
| 1637 | # dynamically changed for a probe function. |
| 1638 | # |
| 1639 | config TRACEPOINTS |
| 1640 | bool |
| 1641 | |
| 1642 | source "arch/Kconfig" |
| 1643 | |
| 1644 | endmenu # General setup |
| 1645 | |
| 1646 | config HAVE_GENERIC_DMA_COHERENT |
| 1647 | bool |
| 1648 | default n |
| 1649 | |
| 1650 | config SLABINFO |
| 1651 | bool |
| 1652 | depends on PROC_FS |
| 1653 | depends on SLAB || SLUB_DEBUG |
| 1654 | default y |
| 1655 | |
| 1656 | config RT_MUTEXES |
| 1657 | boolean |
| 1658 | |
| 1659 | config BASE_SMALL |
| 1660 | int |
| 1661 | default 0 if BASE_FULL |
| 1662 | default 1 if !BASE_FULL |
| 1663 | |
| 1664 | config SYSTEM_TRUSTED_KEYRING |
| 1665 | bool "Provide system-wide ring of trusted keys" |
| 1666 | depends on KEYS |
| 1667 | help |
| 1668 | Provide a system keyring to which trusted keys can be added. Keys in |
| 1669 | the keyring are considered to be trusted. Keys may be added at will |
| 1670 | by the kernel from compiled-in data and from hardware key stores, but |
| 1671 | userspace may only add extra keys if those keys can be verified by |
| 1672 | keys already in the keyring. |
| 1673 | |
| 1674 | Keys in this keyring are used by module signature checking. |
| 1675 | |
| 1676 | menuconfig MODULES |
| 1677 | bool "Enable loadable module support" |
| 1678 | option modules |
| 1679 | help |
| 1680 | Kernel modules are small pieces of compiled code which can |
| 1681 | be inserted in the running kernel, rather than being |
| 1682 | permanently built into the kernel. You use the "modprobe" |
| 1683 | tool to add (and sometimes remove) them. If you say Y here, |
| 1684 | many parts of the kernel can be built as modules (by |
| 1685 | answering M instead of Y where indicated): this is most |
| 1686 | useful for infrequently used options which are not required |
| 1687 | for booting. For more information, see the man pages for |
| 1688 | modprobe, lsmod, modinfo, insmod and rmmod. |
| 1689 | |
| 1690 | If you say Y here, you will need to run "make |
| 1691 | modules_install" to put the modules under /lib/modules/ |
| 1692 | where modprobe can find them (you may need to be root to do |
| 1693 | this). |
| 1694 | |
| 1695 | If unsure, say Y. |
| 1696 | |
| 1697 | if MODULES |
| 1698 | |
| 1699 | config MODULE_FORCE_LOAD |
| 1700 | bool "Forced module loading" |
| 1701 | default n |
| 1702 | help |
| 1703 | Allow loading of modules without version information (ie. modprobe |
| 1704 | --force). Forced module loading sets the 'F' (forced) taint flag and |
| 1705 | is usually a really bad idea. |
| 1706 | |
| 1707 | config MODULE_UNLOAD |
| 1708 | bool "Module unloading" |
| 1709 | help |
| 1710 | Without this option you will not be able to unload any |
| 1711 | modules (note that some modules may not be unloadable |
| 1712 | anyway), which makes your kernel smaller, faster |
| 1713 | and simpler. If unsure, say Y. |
| 1714 | |
| 1715 | config MODULE_FORCE_UNLOAD |
| 1716 | bool "Forced module unloading" |
| 1717 | depends on MODULE_UNLOAD |
| 1718 | help |
| 1719 | This option allows you to force a module to unload, even if the |
| 1720 | kernel believes it is unsafe: the kernel will remove the module |
| 1721 | without waiting for anyone to stop using it (using the -f option to |
| 1722 | rmmod). This is mainly for kernel developers and desperate users. |
| 1723 | If unsure, say N. |
| 1724 | |
| 1725 | config MODVERSIONS |
| 1726 | bool "Module versioning support" |
| 1727 | help |
| 1728 | Usually, you have to use modules compiled with your kernel. |
| 1729 | Saying Y here makes it sometimes possible to use modules |
| 1730 | compiled for different kernels, by adding enough information |
| 1731 | to the modules to (hopefully) spot any changes which would |
| 1732 | make them incompatible with the kernel you are running. If |
| 1733 | unsure, say N. |
| 1734 | |
| 1735 | config MODULE_SRCVERSION_ALL |
| 1736 | bool "Source checksum for all modules" |
| 1737 | help |
| 1738 | Modules which contain a MODULE_VERSION get an extra "srcversion" |
| 1739 | field inserted into their modinfo section, which contains a |
| 1740 | sum of the source files which made it. This helps maintainers |
| 1741 | see exactly which source was used to build a module (since |
| 1742 | others sometimes change the module source without updating |
| 1743 | the version). With this option, such a "srcversion" field |
| 1744 | will be created for all modules. If unsure, say N. |
| 1745 | |
| 1746 | config MODULE_SIG |
| 1747 | bool "Module signature verification" |
| 1748 | depends on MODULES |
| 1749 | select SYSTEM_TRUSTED_KEYRING |
| 1750 | select KEYS |
| 1751 | select CRYPTO |
| 1752 | select ASYMMETRIC_KEY_TYPE |
| 1753 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE |
| 1754 | select PUBLIC_KEY_ALGO_RSA |
| 1755 | select ASN1 |
| 1756 | select OID_REGISTRY |
| 1757 | select X509_CERTIFICATE_PARSER |
| 1758 | help |
| 1759 | Check modules for valid signatures upon load: the signature |
| 1760 | is simply appended to the module. For more information see |
| 1761 | Documentation/module-signing.txt. |
| 1762 | |
| 1763 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
| 1764 | module DOES NOT get stripped after being signed. This includes the |
| 1765 | debuginfo strip done by some packagers (such as rpmbuild) and |
| 1766 | inclusion into an initramfs that wants the module size reduced. |
| 1767 | |
| 1768 | config MODULE_SIG_FORCE |
| 1769 | bool "Require modules to be validly signed" |
| 1770 | depends on MODULE_SIG |
| 1771 | help |
| 1772 | Reject unsigned modules or signed modules for which we don't have a |
| 1773 | key. Without this, such modules will simply taint the kernel. |
| 1774 | |
| 1775 | config MODULE_SIG_ALL |
| 1776 | bool "Automatically sign all modules" |
| 1777 | default y |
| 1778 | depends on MODULE_SIG |
| 1779 | help |
| 1780 | Sign all modules during make modules_install. Without this option, |
| 1781 | modules must be signed manually, using the scripts/sign-file tool. |
| 1782 | |
| 1783 | comment "Do not forget to sign required modules with scripts/sign-file" |
| 1784 | depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL |
| 1785 | |
| 1786 | choice |
| 1787 | prompt "Which hash algorithm should modules be signed with?" |
| 1788 | depends on MODULE_SIG |
| 1789 | help |
| 1790 | This determines which sort of hashing algorithm will be used during |
| 1791 | signature generation. This algorithm _must_ be built into the kernel |
| 1792 | directly so that signature verification can take place. It is not |
| 1793 | possible to load a signed module containing the algorithm to check |
| 1794 | the signature on that module. |
| 1795 | |
| 1796 | config MODULE_SIG_SHA1 |
| 1797 | bool "Sign modules with SHA-1" |
| 1798 | select CRYPTO_SHA1 |
| 1799 | |
| 1800 | config MODULE_SIG_SHA224 |
| 1801 | bool "Sign modules with SHA-224" |
| 1802 | select CRYPTO_SHA256 |
| 1803 | |
| 1804 | config MODULE_SIG_SHA256 |
| 1805 | bool "Sign modules with SHA-256" |
| 1806 | select CRYPTO_SHA256 |
| 1807 | |
| 1808 | config MODULE_SIG_SHA384 |
| 1809 | bool "Sign modules with SHA-384" |
| 1810 | select CRYPTO_SHA512 |
| 1811 | |
| 1812 | config MODULE_SIG_SHA512 |
| 1813 | bool "Sign modules with SHA-512" |
| 1814 | select CRYPTO_SHA512 |
| 1815 | |
| 1816 | endchoice |
| 1817 | |
| 1818 | config MODULE_SIG_HASH |
| 1819 | string |
| 1820 | depends on MODULE_SIG |
| 1821 | default "sha1" if MODULE_SIG_SHA1 |
| 1822 | default "sha224" if MODULE_SIG_SHA224 |
| 1823 | default "sha256" if MODULE_SIG_SHA256 |
| 1824 | default "sha384" if MODULE_SIG_SHA384 |
| 1825 | default "sha512" if MODULE_SIG_SHA512 |
| 1826 | |
| 1827 | endif # MODULES |
| 1828 | |
| 1829 | config INIT_ALL_POSSIBLE |
| 1830 | bool |
| 1831 | help |
| 1832 | Back when each arch used to define their own cpu_online_mask and |
| 1833 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask |
| 1834 | with all 1s, and others with all 0s. When they were centralised, |
| 1835 | it was better to provide this option than to break all the archs |
| 1836 | and have several arch maintainers pursuing me down dark alleys. |
| 1837 | |
| 1838 | config STOP_MACHINE |
| 1839 | bool |
| 1840 | default y |
| 1841 | depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU |
| 1842 | help |
| 1843 | Need stop_machine() primitive. |
| 1844 | |
| 1845 | source "block/Kconfig" |
| 1846 | |
| 1847 | config PREEMPT_NOTIFIERS |
| 1848 | bool |
| 1849 | |
| 1850 | config PADATA |
| 1851 | depends on SMP |
| 1852 | bool |
| 1853 | |
| 1854 | # Can be selected by architectures with broken toolchains |
| 1855 | # that get confused by correct const<->read_only section |
| 1856 | # mappings |
| 1857 | config BROKEN_RODATA |
| 1858 | bool |
| 1859 | |
| 1860 | config ASN1 |
| 1861 | tristate |
| 1862 | help |
| 1863 | Build a simple ASN.1 grammar compiler that produces a bytecode output |
| 1864 | that can be interpreted by the ASN.1 stream decoder and used to |
| 1865 | inform it as to what tags are to be expected in a stream and what |
| 1866 | functions to call on what tags. |
| 1867 | |
| 1868 | source "kernel/Kconfig.locks" |