1config DEFCONFIG_LIST 2 string 3 depends on !UML 4 option defconfig_list 5 default "/lib/modules/$UNAME_RELEASE/.config" 6 default "/etc/kernel-config" 7 default "/boot/config-$UNAME_RELEASE" 8 default "arch/$ARCH/defconfig" 9 10menu "General setup" 11 12config EXPERIMENTAL 13 bool "Prompt for development and/or incomplete code/drivers" 14 ---help--- 15 Some of the various things that Linux supports (such as network 16 drivers, file systems, network protocols, etc.) can be in a state 17 of development where the functionality, stability, or the level of 18 testing is not yet high enough for general use. This is usually 19 known as the "alpha-test" phase among developers. If a feature is 20 currently in alpha-test, then the developers usually discourage 21 uninformed widespread use of this feature by the general public to 22 avoid "Why doesn't this work?" type mail messages. However, active 23 testing and use of these systems is welcomed. Just be aware that it 24 may not meet the normal level of reliability or it may fail to work 25 in some special cases. Detailed bug reports from people familiar 26 with the kernel internals are usually welcomed by the developers 27 (before submitting bug reports, please read the documents 28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 29 <file:Documentation/BUG-HUNTING>, and 30 <file:Documentation/oops-tracing.txt> in the kernel source). 31 32 This option will also make obsoleted drivers available. These are 33 drivers that have been replaced by something else, and/or are 34 scheduled to be removed in a future kernel release. 35 36 Unless you intend to help test and develop a feature or driver that 37 falls into this category, or you have a situation that requires 38 using these features, you should probably say N here, which will 39 cause the configurator to present you with fewer choices. If 40 you say Y here, you will be offered the choice of using features or 41 drivers that are currently considered to be in the alpha-test phase. 42 43config BROKEN 44 bool 45 46config BROKEN_ON_SMP 47 bool 48 depends on BROKEN || !SMP 49 default y 50 51config LOCK_KERNEL 52 bool 53 depends on SMP || PREEMPT 54 default y 55 56config INIT_ENV_ARG_LIMIT 57 int 58 default 32 if !UML 59 default 128 if UML 60 help 61 Maximum of each of the number of arguments and environment 62 variables passed to init from the kernel command line. 63 64 65config LOCALVERSION 66 string "Local version - append to kernel release" 67 help 68 Append an extra string to the end of your kernel version. 69 This will show up when you type uname, for example. 70 The string you set here will be appended after the contents of 71 any files with a filename matching localversion* in your 72 object and source tree, in that order. Your total string can 73 be a maximum of 64 characters. 74 75config LOCALVERSION_AUTO 76 bool "Automatically append version information to the version string" 77 default y 78 help 79 This will try to automatically determine if the current tree is a 80 release tree by looking for git tags that belong to the current 81 top of tree revision. 82 83 A string of the format -gxxxxxxxx will be added to the localversion 84 if a git-based tree is found. The string generated by this will be 85 appended after any matching localversion* files, and after the value 86 set in CONFIG_LOCALVERSION. 87 88 (The actual string used here is the first eight characters produced 89 by running the command: 90 91 $ git rev-parse --verify HEAD 92 93 which is done within the script "scripts/setlocalversion".) 94 95config SWAP 96 bool "Support for paging of anonymous memory (swap)" 97 depends on MMU && BLOCK 98 default y 99 help 100 This option allows you to choose whether you want to have support 101 for so called swap devices or swap files in your kernel that are 102 used to provide more virtual memory than the actual RAM present 103 in your computer. If unsure say Y. 104 105config SYSVIPC 106 bool "System V IPC" 107 ---help--- 108 Inter Process Communication is a suite of library functions and 109 system calls which let processes (running programs) synchronize and 110 exchange information. It is generally considered to be a good thing, 111 and some programs won't run unless you say Y here. In particular, if 112 you want to run the DOS emulator dosemu under Linux (read the 113 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 114 you'll need to say Y here. 115 116 You can find documentation about IPC with "info ipc" and also in 117 section 6.4 of the Linux Programmer's Guide, available from 118 <http://www.tldp.org/guides.html>. 119 120config SYSVIPC_SYSCTL 121 bool 122 depends on SYSVIPC 123 depends on SYSCTL 124 default y 125 126config POSIX_MQUEUE 127 bool "POSIX Message Queues" 128 depends on NET && EXPERIMENTAL 129 ---help--- 130 POSIX variant of message queues is a part of IPC. In POSIX message 131 queues every message has a priority which decides about succession 132 of receiving it by a process. If you want to compile and run 133 programs written e.g. for Solaris with use of its POSIX message 134 queues (functions mq_*) say Y here. 135 136 POSIX message queues are visible as a filesystem called 'mqueue' 137 and can be mounted somewhere if you want to do filesystem 138 operations on message queues. 139 140 If unsure, say Y. 141 142config BSD_PROCESS_ACCT 143 bool "BSD Process Accounting" 144 help 145 If you say Y here, a user level program will be able to instruct the 146 kernel (via a special system call) to write process accounting 147 information to a file: whenever a process exits, information about 148 that process will be appended to the file by the kernel. The 149 information includes things such as creation time, owning user, 150 command name, memory usage, controlling terminal etc. (the complete 151 list is in the struct acct in <file:include/linux/acct.h>). It is 152 up to the user level program to do useful things with this 153 information. This is generally a good idea, so say Y. 154 155config BSD_PROCESS_ACCT_V3 156 bool "BSD Process Accounting version 3 file format" 157 depends on BSD_PROCESS_ACCT 158 default n 159 help 160 If you say Y here, the process accounting information is written 161 in a new file format that also logs the process IDs of each 162 process and it's parent. Note that this file format is incompatible 163 with previous v0/v1/v2 file formats, so you will need updated tools 164 for processing it. A preliminary version of these tools is available 165 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 166 167config TASKSTATS 168 bool "Export task/process statistics through netlink (EXPERIMENTAL)" 169 depends on NET 170 default n 171 help 172 Export selected statistics for tasks/processes through the 173 generic netlink interface. Unlike BSD process accounting, the 174 statistics are available during the lifetime of tasks/processes as 175 responses to commands. Like BSD accounting, they are sent to user 176 space on task exit. 177 178 Say N if unsure. 179 180config TASK_DELAY_ACCT 181 bool "Enable per-task delay accounting (EXPERIMENTAL)" 182 depends on TASKSTATS 183 help 184 Collect information on time spent by a task waiting for system 185 resources like cpu, synchronous block I/O completion and swapping 186 in pages. Such statistics can help in setting a task's priorities 187 relative to other tasks for cpu, io, rss limits etc. 188 189 Say N if unsure. 190 191config TASK_XACCT 192 bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 193 depends on TASKSTATS 194 help 195 Collect extended task accounting data and send the data 196 to userland for processing over the taskstats interface. 197 198 Say N if unsure. 199 200config TASK_IO_ACCOUNTING 201 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 202 depends on TASK_XACCT 203 help 204 Collect information on the number of bytes of storage I/O which this 205 task has caused. 206 207 Say N if unsure. 208 209config USER_NS 210 bool "User Namespaces (EXPERIMENTAL)" 211 default n 212 depends on EXPERIMENTAL 213 help 214 Support user namespaces. This allows containers, i.e. 215 vservers, to use user namespaces to provide different 216 user info for different servers. If unsure, say N. 217 218config AUDIT 219 bool "Auditing support" 220 depends on NET 221 help 222 Enable auditing infrastructure that can be used with another 223 kernel subsystem, such as SELinux (which requires this for 224 logging of avc messages output). Does not do system-call 225 auditing without CONFIG_AUDITSYSCALL. 226 227config AUDITSYSCALL 228 bool "Enable system-call auditing support" 229 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64) 230 default y if SECURITY_SELINUX 231 help 232 Enable low-overhead system-call auditing infrastructure that 233 can be used independently or with another kernel subsystem, 234 such as SELinux. To use audit's filesystem watch feature, please 235 ensure that INOTIFY is configured. 236 237config IKCONFIG 238 tristate "Kernel .config support" 239 ---help--- 240 This option enables the complete Linux kernel ".config" file 241 contents to be saved in the kernel. It provides documentation 242 of which kernel options are used in a running kernel or in an 243 on-disk kernel. This information can be extracted from the kernel 244 image file with the script scripts/extract-ikconfig and used as 245 input to rebuild the current kernel or to build another kernel. 246 It can also be extracted from a running kernel by reading 247 /proc/config.gz if enabled (below). 248 249config IKCONFIG_PROC 250 bool "Enable access to .config through /proc/config.gz" 251 depends on IKCONFIG && PROC_FS 252 ---help--- 253 This option enables access to the kernel configuration file 254 through /proc/config.gz. 255 256config LOG_BUF_SHIFT 257 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 258 range 12 21 259 default 17 if S390 || LOCKDEP 260 default 16 if X86_NUMAQ || IA64 261 default 15 if SMP 262 default 14 263 help 264 Select kernel log buffer size as a power of 2. 265 Defaults and Examples: 266 17 => 128 KB for S/390 267 16 => 64 KB for x86 NUMAQ or IA-64 268 15 => 32 KB for SMP 269 14 => 16 KB for uniprocessor 270 13 => 8 KB 271 12 => 4 KB 272 273config CPUSETS 274 bool "Cpuset support" 275 depends on SMP 276 help 277 This option will let you create and manage CPUSETs which 278 allow dynamically partitioning a system into sets of CPUs and 279 Memory Nodes and assigning tasks to run only within those sets. 280 This is primarily useful on large SMP or NUMA systems. 281 282 Say N if unsure. 283 284config FAIR_GROUP_SCHED 285 bool "Fair group CPU scheduler" 286 default y 287 depends on EXPERIMENTAL 288 help 289 This feature lets CPU scheduler recognize task groups and control CPU 290 bandwidth allocation to such task groups. 291 292choice 293 depends on FAIR_GROUP_SCHED 294 prompt "Basis for grouping tasks" 295 default FAIR_USER_SCHED 296 297config FAIR_USER_SCHED 298 bool "user id" 299 help 300 This option will choose userid as the basis for grouping 301 tasks, thus providing equal CPU bandwidth to each user. 302 303endchoice 304 305config SYSFS_DEPRECATED 306 bool "Create deprecated sysfs files" 307 default y 308 help 309 This option creates deprecated symlinks such as the 310 "device"-link, the <subsystem>:<name>-link, and the 311 "bus"-link. It may also add deprecated key in the 312 uevent environment. 313 None of these features or values should be used today, as 314 they export driver core implementation details to userspace 315 or export properties which can't be kept stable across kernel 316 releases. 317 318 If enabled, this option will also move any device structures 319 that belong to a class, back into the /sys/class hierarchy, in 320 order to support older versions of udev. 321 322 If you are using a distro that was released in 2006 or later, 323 it should be safe to say N here. 324 325config RELAY 326 bool "Kernel->user space relay support (formerly relayfs)" 327 help 328 This option enables support for relay interface support in 329 certain file systems (such as debugfs). 330 It is designed to provide an efficient mechanism for tools and 331 facilities to relay large amounts of data from kernel space to 332 user space. 333 334 If unsure, say N. 335 336config BLK_DEV_INITRD 337 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 338 depends on BROKEN || !FRV 339 help 340 The initial RAM filesystem is a ramfs which is loaded by the 341 boot loader (loadlin or lilo) and that is mounted as root 342 before the normal boot procedure. It is typically used to 343 load modules needed to mount the "real" root file system, 344 etc. See <file:Documentation/initrd.txt> for details. 345 346 If RAM disk support (BLK_DEV_RAM) is also included, this 347 also enables initial RAM disk (initrd) support and adds 348 15 Kbytes (more on some other architectures) to the kernel size. 349 350 If unsure say Y. 351 352if BLK_DEV_INITRD 353 354source "usr/Kconfig" 355 356endif 357 358config CC_OPTIMIZE_FOR_SIZE 359 bool "Optimize for size (Look out for broken compilers!)" 360 default y 361 depends on ARM || H8300 || SUPERH || EXPERIMENTAL 362 help 363 Enabling this option will pass "-Os" instead of "-O2" to gcc 364 resulting in a smaller kernel. 365 366 WARNING: some versions of gcc may generate incorrect code with this 367 option. If problems are observed, a gcc upgrade may be needed. 368 369 If unsure, say N. 370 371config SYSCTL 372 bool 373 374menuconfig EMBEDDED 375 bool "Configure standard kernel features (for small systems)" 376 help 377 This option allows certain base kernel options and settings 378 to be disabled or tweaked. This is for specialized 379 environments which can tolerate a "non-standard" kernel. 380 Only use this if you really know what you are doing. 381 382config UID16 383 bool "Enable 16-bit UID system calls" if EMBEDDED 384 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 385 default y 386 help 387 This enables the legacy 16-bit UID syscall wrappers. 388 389config SYSCTL_SYSCALL 390 bool "Sysctl syscall support" if EMBEDDED 391 default y 392 select SYSCTL 393 ---help--- 394 sys_sysctl uses binary paths that have been found challenging 395 to properly maintain and use. The interface in /proc/sys 396 using paths with ascii names is now the primary path to this 397 information. 398 399 Almost nothing using the binary sysctl interface so if you are 400 trying to save some space it is probably safe to disable this, 401 making your kernel marginally smaller. 402 403 If unsure say Y here. 404 405config KALLSYMS 406 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 407 default y 408 help 409 Say Y here to let the kernel print out symbolic crash information and 410 symbolic stack backtraces. This increases the size of the kernel 411 somewhat, as all symbols have to be loaded into the kernel image. 412 413config KALLSYMS_ALL 414 bool "Include all symbols in kallsyms" 415 depends on DEBUG_KERNEL && KALLSYMS 416 help 417 Normally kallsyms only contains the symbols of functions, for nicer 418 OOPS messages. Some debuggers can use kallsyms for other 419 symbols too: say Y here to include all symbols, if you need them 420 and you don't care about adding 300k to the size of your kernel. 421 422 Say N. 423 424config KALLSYMS_EXTRA_PASS 425 bool "Do an extra kallsyms pass" 426 depends on KALLSYMS 427 help 428 If kallsyms is not working correctly, the build will fail with 429 inconsistent kallsyms data. If that occurs, log a bug report and 430 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 431 Always say N here unless you find a bug in kallsyms, which must be 432 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 433 you wait for kallsyms to be fixed. 434 435 436config HOTPLUG 437 bool "Support for hot-pluggable devices" if EMBEDDED 438 default y 439 help 440 This option is provided for the case where no hotplug or uevent 441 capabilities is wanted by the kernel. You should only consider 442 disabling this option for embedded systems that do not use modules, a 443 dynamic /dev tree, or dynamic device discovery. Just say Y. 444 445config PRINTK 446 default y 447 bool "Enable support for printk" if EMBEDDED 448 help 449 This option enables normal printk support. Removing it 450 eliminates most of the message strings from the kernel image 451 and makes the kernel more or less silent. As this makes it 452 very difficult to diagnose system problems, saying N here is 453 strongly discouraged. 454 455config BUG 456 bool "BUG() support" if EMBEDDED 457 default y 458 help 459 Disabling this option eliminates support for BUG and WARN, reducing 460 the size of your kernel image and potentially quietly ignoring 461 numerous fatal conditions. You should only consider disabling this 462 option for embedded systems with no facilities for reporting errors. 463 Just say Y. 464 465config ELF_CORE 466 default y 467 bool "Enable ELF core dumps" if EMBEDDED 468 help 469 Enable support for generating core dumps. Disabling saves about 4k. 470 471config BASE_FULL 472 default y 473 bool "Enable full-sized data structures for core" if EMBEDDED 474 help 475 Disabling this option reduces the size of miscellaneous core 476 kernel data structures. This saves memory on small machines, 477 but may reduce performance. 478 479config FUTEX 480 bool "Enable futex support" if EMBEDDED 481 default y 482 select RT_MUTEXES 483 help 484 Disabling this option will cause the kernel to be built without 485 support for "fast userspace mutexes". The resulting kernel may not 486 run glibc-based applications correctly. 487 488config ANON_INODES 489 bool 490 491config EPOLL 492 bool "Enable eventpoll support" if EMBEDDED 493 default y 494 select ANON_INODES 495 help 496 Disabling this option will cause the kernel to be built without 497 support for epoll family of system calls. 498 499config SIGNALFD 500 bool "Enable signalfd() system call" if EMBEDDED 501 select ANON_INODES 502 default y 503 help 504 Enable the signalfd() system call that allows to receive signals 505 on a file descriptor. 506 507 If unsure, say Y. 508 509config TIMERFD 510 bool "Enable timerfd() system call" if EMBEDDED 511 select ANON_INODES 512 depends on BROKEN 513 default y 514 help 515 Enable the timerfd() system call that allows to receive timer 516 events on a file descriptor. 517 518 If unsure, say Y. 519 520config EVENTFD 521 bool "Enable eventfd() system call" if EMBEDDED 522 select ANON_INODES 523 default y 524 help 525 Enable the eventfd() system call that allows to receive both 526 kernel notification (ie. KAIO) or userspace notifications. 527 528 If unsure, say Y. 529 530config SHMEM 531 bool "Use full shmem filesystem" if EMBEDDED 532 default y 533 depends on MMU 534 help 535 The shmem is an internal filesystem used to manage shared memory. 536 It is backed by swap and manages resource limits. It is also exported 537 to userspace as tmpfs if TMPFS is enabled. Disabling this 538 option replaces shmem and tmpfs with the much simpler ramfs code, 539 which may be appropriate on small systems without swap. 540 541config VM_EVENT_COUNTERS 542 default y 543 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 544 help 545 VM event counters are needed for event counts to be shown. 546 This option allows the disabling of the VM event counters 547 on EMBEDDED systems. /proc/vmstat will only show page counts 548 if VM event counters are disabled. 549 550config SLUB_DEBUG 551 default y 552 bool "Enable SLUB debugging support" if EMBEDDED 553 depends on SLUB 554 help 555 SLUB has extensive debug support features. Disabling these can 556 result in significant savings in code size. This also disables 557 SLUB sysfs support. /sys/slab will not exist and there will be 558 no support for cache validation etc. 559 560choice 561 prompt "Choose SLAB allocator" 562 default SLUB 563 help 564 This option allows to select a slab allocator. 565 566config SLAB 567 bool "SLAB" 568 help 569 The regular slab allocator that is established and known to work 570 well in all environments. It organizes cache hot objects in 571 per cpu and per node queues. SLAB is the default choice for 572 a slab allocator. 573 574config SLUB 575 bool "SLUB (Unqueued Allocator)" 576 help 577 SLUB is a slab allocator that minimizes cache line usage 578 instead of managing queues of cached objects (SLAB approach). 579 Per cpu caching is realized using slabs of objects instead 580 of queues of objects. SLUB can use memory efficiently 581 and has enhanced diagnostics. 582 583config SLOB 584 depends on EMBEDDED 585 bool "SLOB (Simple Allocator)" 586 help 587 SLOB replaces the SLAB allocator with a drastically simpler 588 allocator. SLOB is more space efficient than SLAB but does not 589 scale well (single lock for all operations) and is also highly 590 susceptible to fragmentation. SLUB can accomplish a higher object 591 density. It is usually better to use SLUB instead of SLOB. 592 593endchoice 594 595endmenu # General setup 596 597config RT_MUTEXES 598 boolean 599 select PLIST 600 601config TINY_SHMEM 602 default !SHMEM 603 bool 604 605config BASE_SMALL 606 int 607 default 0 if BASE_FULL 608 default 1 if !BASE_FULL 609 610menuconfig MODULES 611 bool "Enable loadable module support" 612 help 613 Kernel modules are small pieces of compiled code which can 614 be inserted in the running kernel, rather than being 615 permanently built into the kernel. You use the "modprobe" 616 tool to add (and sometimes remove) them. If you say Y here, 617 many parts of the kernel can be built as modules (by 618 answering M instead of Y where indicated): this is most 619 useful for infrequently used options which are not required 620 for booting. For more information, see the man pages for 621 modprobe, lsmod, modinfo, insmod and rmmod. 622 623 If you say Y here, you will need to run "make 624 modules_install" to put the modules under /lib/modules/ 625 where modprobe can find them (you may need to be root to do 626 this). 627 628 If unsure, say Y. 629 630config MODULE_UNLOAD 631 bool "Module unloading" 632 depends on MODULES 633 help 634 Without this option you will not be able to unload any 635 modules (note that some modules may not be unloadable 636 anyway), which makes your kernel slightly smaller and 637 simpler. If unsure, say Y. 638 639config MODULE_FORCE_UNLOAD 640 bool "Forced module unloading" 641 depends on MODULE_UNLOAD && EXPERIMENTAL 642 help 643 This option allows you to force a module to unload, even if the 644 kernel believes it is unsafe: the kernel will remove the module 645 without waiting for anyone to stop using it (using the -f option to 646 rmmod). This is mainly for kernel developers and desperate users. 647 If unsure, say N. 648 649config MODVERSIONS 650 bool "Module versioning support" 651 depends on MODULES 652 help 653 Usually, you have to use modules compiled with your kernel. 654 Saying Y here makes it sometimes possible to use modules 655 compiled for different kernels, by adding enough information 656 to the modules to (hopefully) spot any changes which would 657 make them incompatible with the kernel you are running. If 658 unsure, say N. 659 660config MODULE_SRCVERSION_ALL 661 bool "Source checksum for all modules" 662 depends on MODULES 663 help 664 Modules which contain a MODULE_VERSION get an extra "srcversion" 665 field inserted into their modinfo section, which contains a 666 sum of the source files which made it. This helps maintainers 667 see exactly which source was used to build a module (since 668 others sometimes change the module source without updating 669 the version). With this option, such a "srcversion" field 670 will be created for all modules. If unsure, say N. 671 672config KMOD 673 bool "Automatic kernel module loading" 674 depends on MODULES 675 help 676 Normally when you have selected some parts of the kernel to 677 be created as kernel modules, you must load them (using the 678 "modprobe" command) before you can use them. If you say Y 679 here, some parts of the kernel will be able to load modules 680 automatically: when a part of the kernel needs a module, it 681 runs modprobe with the appropriate arguments, thereby 682 loading the module if it is available. If unsure, say Y. 683 684config STOP_MACHINE 685 bool 686 default y 687 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 688 help 689 Need stop_machine() primitive. 690 691source "block/Kconfig" 692