1config ARCH 2 string 3 option env="ARCH" 4 5config KERNELVERSION 6 string 7 option env="KERNELVERSION" 8 9config 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/$ARCH/defconfig" 17 18menu "General setup" 19 20config EXPERIMENTAL 21 bool "Prompt for development and/or incomplete code/drivers" 22 ---help--- 23 Some of the various things that Linux supports (such as network 24 drivers, file systems, network protocols, etc.) can be in a state 25 of development where the functionality, stability, or the level of 26 testing is not yet high enough for general use. This is usually 27 known as the "alpha-test" phase among developers. If a feature is 28 currently in alpha-test, then the developers usually discourage 29 uninformed widespread use of this feature by the general public to 30 avoid "Why doesn't this work?" type mail messages. However, active 31 testing and use of these systems is welcomed. Just be aware that it 32 may not meet the normal level of reliability or it may fail to work 33 in some special cases. Detailed bug reports from people familiar 34 with the kernel internals are usually welcomed by the developers 35 (before submitting bug reports, please read the documents 36 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 37 <file:Documentation/BUG-HUNTING>, and 38 <file:Documentation/oops-tracing.txt> in the kernel source). 39 40 This option will also make obsoleted drivers available. These are 41 drivers that have been replaced by something else, and/or are 42 scheduled to be removed in a future kernel release. 43 44 Unless you intend to help test and develop a feature or driver that 45 falls into this category, or you have a situation that requires 46 using these features, you should probably say N here, which will 47 cause the configurator to present you with fewer choices. If 48 you say Y here, you will be offered the choice of using features or 49 drivers that are currently considered to be in the alpha-test phase. 50 51config BROKEN 52 bool 53 54config BROKEN_ON_SMP 55 bool 56 depends on BROKEN || !SMP 57 default y 58 59config LOCK_KERNEL 60 bool 61 depends on SMP || PREEMPT 62 default y 63 64config INIT_ENV_ARG_LIMIT 65 int 66 default 32 if !UML 67 default 128 if UML 68 help 69 Maximum of each of the number of arguments and environment 70 variables passed to init from the kernel command line. 71 72 73config LOCALVERSION 74 string "Local version - append to kernel release" 75 help 76 Append an extra string to the end of your kernel version. 77 This will show up when you type uname, for example. 78 The string you set here will be appended after the contents of 79 any files with a filename matching localversion* in your 80 object and source tree, in that order. Your total string can 81 be a maximum of 64 characters. 82 83config LOCALVERSION_AUTO 84 bool "Automatically append version information to the version string" 85 default y 86 help 87 This will try to automatically determine if the current tree is a 88 release tree by looking for git tags that belong to the current 89 top of tree revision. 90 91 A string of the format -gxxxxxxxx will be added to the localversion 92 if a git-based tree is found. The string generated by this will be 93 appended after any matching localversion* files, and after the value 94 set in CONFIG_LOCALVERSION. 95 96 (The actual string used here is the first eight characters produced 97 by running the command: 98 99 $ git rev-parse --verify HEAD 100 101 which is done within the script "scripts/setlocalversion".) 102 103config SWAP 104 bool "Support for paging of anonymous memory (swap)" 105 depends on MMU && BLOCK 106 default y 107 help 108 This option allows you to choose whether you want to have support 109 for so called swap devices or swap files in your kernel that are 110 used to provide more virtual memory than the actual RAM present 111 in your computer. If unsure say Y. 112 113config SYSVIPC 114 bool "System V IPC" 115 ---help--- 116 Inter Process Communication is a suite of library functions and 117 system calls which let processes (running programs) synchronize and 118 exchange information. It is generally considered to be a good thing, 119 and some programs won't run unless you say Y here. In particular, if 120 you want to run the DOS emulator dosemu under Linux (read the 121 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 122 you'll need to say Y here. 123 124 You can find documentation about IPC with "info ipc" and also in 125 section 6.4 of the Linux Programmer's Guide, available from 126 <http://www.tldp.org/guides.html>. 127 128config SYSVIPC_SYSCTL 129 bool 130 depends on SYSVIPC 131 depends on SYSCTL 132 default y 133 134config POSIX_MQUEUE 135 bool "POSIX Message Queues" 136 depends on NET && EXPERIMENTAL 137 ---help--- 138 POSIX variant of message queues is a part of IPC. In POSIX message 139 queues every message has a priority which decides about succession 140 of receiving it by a process. If you want to compile and run 141 programs written e.g. for Solaris with use of its POSIX message 142 queues (functions mq_*) say Y here. 143 144 POSIX message queues are visible as a filesystem called 'mqueue' 145 and can be mounted somewhere if you want to do filesystem 146 operations on message queues. 147 148 If unsure, say Y. 149 150config BSD_PROCESS_ACCT 151 bool "BSD Process Accounting" 152 help 153 If you say Y here, a user level program will be able to instruct the 154 kernel (via a special system call) to write process accounting 155 information to a file: whenever a process exits, information about 156 that process will be appended to the file by the kernel. The 157 information includes things such as creation time, owning user, 158 command name, memory usage, controlling terminal etc. (the complete 159 list is in the struct acct in <file:include/linux/acct.h>). It is 160 up to the user level program to do useful things with this 161 information. This is generally a good idea, so say Y. 162 163config BSD_PROCESS_ACCT_V3 164 bool "BSD Process Accounting version 3 file format" 165 depends on BSD_PROCESS_ACCT 166 default n 167 help 168 If you say Y here, the process accounting information is written 169 in a new file format that also logs the process IDs of each 170 process and it's parent. Note that this file format is incompatible 171 with previous v0/v1/v2 file formats, so you will need updated tools 172 for processing it. A preliminary version of these tools is available 173 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 174 175config TASKSTATS 176 bool "Export task/process statistics through netlink (EXPERIMENTAL)" 177 depends on NET 178 default n 179 help 180 Export selected statistics for tasks/processes through the 181 generic netlink interface. Unlike BSD process accounting, the 182 statistics are available during the lifetime of tasks/processes as 183 responses to commands. Like BSD accounting, they are sent to user 184 space on task exit. 185 186 Say N if unsure. 187 188config TASK_DELAY_ACCT 189 bool "Enable per-task delay accounting (EXPERIMENTAL)" 190 depends on TASKSTATS 191 help 192 Collect information on time spent by a task waiting for system 193 resources like cpu, synchronous block I/O completion and swapping 194 in pages. Such statistics can help in setting a task's priorities 195 relative to other tasks for cpu, io, rss limits etc. 196 197 Say N if unsure. 198 199config TASK_XACCT 200 bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 201 depends on TASKSTATS 202 help 203 Collect extended task accounting data and send the data 204 to userland for processing over the taskstats interface. 205 206 Say N if unsure. 207 208config TASK_IO_ACCOUNTING 209 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 210 depends on TASK_XACCT 211 help 212 Collect information on the number of bytes of storage I/O which this 213 task has caused. 214 215 Say N if unsure. 216 217config AUDIT 218 bool "Auditing support" 219 depends on NET 220 help 221 Enable auditing infrastructure that can be used with another 222 kernel subsystem, such as SELinux (which requires this for 223 logging of avc messages output). Does not do system-call 224 auditing without CONFIG_AUDITSYSCALL. 225 226config AUDITSYSCALL 227 bool "Enable system-call auditing support" 228 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH) 229 default y if SECURITY_SELINUX 230 help 231 Enable low-overhead system-call auditing infrastructure that 232 can be used independently or with another kernel subsystem, 233 such as SELinux. To use audit's filesystem watch feature, please 234 ensure that INOTIFY is configured. 235 236config AUDIT_TREE 237 def_bool y 238 depends on AUDITSYSCALL && INOTIFY 239 240config IKCONFIG 241 tristate "Kernel .config support" 242 ---help--- 243 This option enables the complete Linux kernel ".config" file 244 contents to be saved in the kernel. It provides documentation 245 of which kernel options are used in a running kernel or in an 246 on-disk kernel. This information can be extracted from the kernel 247 image file with the script scripts/extract-ikconfig and used as 248 input to rebuild the current kernel or to build another kernel. 249 It can also be extracted from a running kernel by reading 250 /proc/config.gz if enabled (below). 251 252config IKCONFIG_PROC 253 bool "Enable access to .config through /proc/config.gz" 254 depends on IKCONFIG && PROC_FS 255 ---help--- 256 This option enables access to the kernel configuration file 257 through /proc/config.gz. 258 259config LOG_BUF_SHIFT 260 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 261 range 12 21 262 default 17 if S390 || LOCKDEP 263 default 16 if X86_NUMAQ || IA64 264 default 15 if SMP 265 default 14 266 help 267 Select kernel log buffer size as a power of 2. 268 Defaults and Examples: 269 17 => 128 KB for S/390 270 16 => 64 KB for x86 NUMAQ or IA-64 271 15 => 32 KB for SMP 272 14 => 16 KB for uniprocessor 273 13 => 8 KB 274 12 => 4 KB 275 276config CGROUPS 277 bool "Control Group support" 278 help 279 This option will let you use process cgroup subsystems 280 such as Cpusets 281 282 Say N if unsure. 283 284config CGROUP_DEBUG 285 bool "Example debug cgroup subsystem" 286 depends on CGROUPS 287 help 288 This option enables a simple cgroup subsystem that 289 exports useful debugging information about the cgroups 290 framework 291 292 Say N if unsure 293 294config CGROUP_NS 295 bool "Namespace cgroup subsystem" 296 depends on CGROUPS 297 help 298 Provides a simple namespace cgroup subsystem to 299 provide hierarchical naming of sets of namespaces, 300 for instance virtual servers and checkpoint/restart 301 jobs. 302 303config CPUSETS 304 bool "Cpuset support" 305 depends on SMP && CGROUPS 306 help 307 This option will let you create and manage CPUSETs which 308 allow dynamically partitioning a system into sets of CPUs and 309 Memory Nodes and assigning tasks to run only within those sets. 310 This is primarily useful on large SMP or NUMA systems. 311 312 Say N if unsure. 313 314config GROUP_SCHED 315 bool "Group CPU scheduler" 316 default y 317 help 318 This feature lets CPU scheduler recognize task groups and control CPU 319 bandwidth allocation to such task groups. 320 321config FAIR_GROUP_SCHED 322 bool "Group scheduling for SCHED_OTHER" 323 depends on GROUP_SCHED 324 default y 325 326config RT_GROUP_SCHED 327 bool "Group scheduling for SCHED_RR/FIFO" 328 depends on EXPERIMENTAL 329 depends on GROUP_SCHED 330 default n 331 332choice 333 depends on GROUP_SCHED 334 prompt "Basis for grouping tasks" 335 default USER_SCHED 336 337config USER_SCHED 338 bool "user id" 339 help 340 This option will choose userid as the basis for grouping 341 tasks, thus providing equal CPU bandwidth to each user. 342 343config CGROUP_SCHED 344 bool "Control groups" 345 depends on CGROUPS 346 help 347 This option allows you to create arbitrary task groups 348 using the "cgroup" pseudo filesystem and control 349 the cpu bandwidth allocated to each such task group. 350 Refer to Documentation/cgroups.txt for more information 351 on "cgroup" pseudo filesystem. 352 353endchoice 354 355config CGROUP_CPUACCT 356 bool "Simple CPU accounting cgroup subsystem" 357 depends on CGROUPS 358 help 359 Provides a simple Resource Controller for monitoring the 360 total CPU consumed by the tasks in a cgroup 361 362config RESOURCE_COUNTERS 363 bool "Resource counters" 364 help 365 This option enables controller independent resource accounting 366 infrastructure that works with cgroups 367 depends on CGROUPS 368 369config SYSFS_DEPRECATED 370 bool "Create deprecated sysfs files" 371 depends on SYSFS 372 default y 373 help 374 This option creates deprecated symlinks such as the 375 "device"-link, the <subsystem>:<name>-link, and the 376 "bus"-link. It may also add deprecated key in the 377 uevent environment. 378 None of these features or values should be used today, as 379 they export driver core implementation details to userspace 380 or export properties which can't be kept stable across kernel 381 releases. 382 383 If enabled, this option will also move any device structures 384 that belong to a class, back into the /sys/class hierarchy, in 385 order to support older versions of udev. 386 387 If you are using a distro that was released in 2006 or later, 388 it should be safe to say N here. 389 390config CGROUP_MEM_CONT 391 bool "Memory controller for cgroups" 392 depends on CGROUPS && RESOURCE_COUNTERS 393 help 394 Provides a memory controller that manages both page cache and 395 RSS memory. 396 397config PROC_PID_CPUSET 398 bool "Include legacy /proc/<pid>/cpuset file" 399 depends on CPUSETS 400 default y 401 402config RELAY 403 bool "Kernel->user space relay support (formerly relayfs)" 404 help 405 This option enables support for relay interface support in 406 certain file systems (such as debugfs). 407 It is designed to provide an efficient mechanism for tools and 408 facilities to relay large amounts of data from kernel space to 409 user space. 410 411 If unsure, say N. 412 413config NAMESPACES 414 bool "Namespaces support" if EMBEDDED 415 default !EMBEDDED 416 help 417 Provides the way to make tasks work with different objects using 418 the same id. For example same IPC id may refer to different objects 419 or same user id or pid may refer to different tasks when used in 420 different namespaces. 421 422config UTS_NS 423 bool "UTS namespace" 424 depends on NAMESPACES 425 help 426 In this namespace tasks see different info provided with the 427 uname() system call 428 429config IPC_NS 430 bool "IPC namespace" 431 depends on NAMESPACES && SYSVIPC 432 help 433 In this namespace tasks work with IPC ids which correspond to 434 different IPC objects in different namespaces 435 436config USER_NS 437 bool "User namespace (EXPERIMENTAL)" 438 depends on NAMESPACES && EXPERIMENTAL 439 help 440 This allows containers, i.e. vservers, to use user namespaces 441 to provide different user info for different servers. 442 If unsure, say N. 443 444config PID_NS 445 bool "PID Namespaces (EXPERIMENTAL)" 446 default n 447 depends on NAMESPACES && EXPERIMENTAL 448 help 449 Suport process id namespaces. This allows having multiple 450 process with the same pid as long as they are in different 451 pid namespaces. This is a building block of containers. 452 453 Unless you want to work with an experimental feature 454 say N here. 455 456config BLK_DEV_INITRD 457 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 458 depends on BROKEN || !FRV 459 help 460 The initial RAM filesystem is a ramfs which is loaded by the 461 boot loader (loadlin or lilo) and that is mounted as root 462 before the normal boot procedure. It is typically used to 463 load modules needed to mount the "real" root file system, 464 etc. See <file:Documentation/initrd.txt> for details. 465 466 If RAM disk support (BLK_DEV_RAM) is also included, this 467 also enables initial RAM disk (initrd) support and adds 468 15 Kbytes (more on some other architectures) to the kernel size. 469 470 If unsure say Y. 471 472if BLK_DEV_INITRD 473 474source "usr/Kconfig" 475 476endif 477 478config CC_OPTIMIZE_FOR_SIZE 479 bool "Optimize for size (Look out for broken compilers!)" 480 default y 481 depends on ARM || H8300 || SUPERH || EXPERIMENTAL 482 help 483 Enabling this option will pass "-Os" instead of "-O2" to gcc 484 resulting in a smaller kernel. 485 486 WARNING: some versions of gcc may generate incorrect code with this 487 option. If problems are observed, a gcc upgrade may be needed. 488 489 If unsure, say N. 490 491config SYSCTL 492 bool 493 494menuconfig EMBEDDED 495 bool "Configure standard kernel features (for small systems)" 496 help 497 This option allows certain base kernel options and settings 498 to be disabled or tweaked. This is for specialized 499 environments which can tolerate a "non-standard" kernel. 500 Only use this if you really know what you are doing. 501 502config UID16 503 bool "Enable 16-bit UID system calls" if EMBEDDED 504 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 505 default y 506 help 507 This enables the legacy 16-bit UID syscall wrappers. 508 509config SYSCTL_SYSCALL 510 bool "Sysctl syscall support" if EMBEDDED 511 default y 512 select SYSCTL 513 ---help--- 514 sys_sysctl uses binary paths that have been found challenging 515 to properly maintain and use. The interface in /proc/sys 516 using paths with ascii names is now the primary path to this 517 information. 518 519 Almost nothing using the binary sysctl interface so if you are 520 trying to save some space it is probably safe to disable this, 521 making your kernel marginally smaller. 522 523 If unsure say Y here. 524 525config KALLSYMS 526 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 527 default y 528 help 529 Say Y here to let the kernel print out symbolic crash information and 530 symbolic stack backtraces. This increases the size of the kernel 531 somewhat, as all symbols have to be loaded into the kernel image. 532 533config KALLSYMS_ALL 534 bool "Include all symbols in kallsyms" 535 depends on DEBUG_KERNEL && KALLSYMS 536 help 537 Normally kallsyms only contains the symbols of functions, for nicer 538 OOPS messages. Some debuggers can use kallsyms for other 539 symbols too: say Y here to include all symbols, if you need them 540 and you don't care about adding 300k to the size of your kernel. 541 542 Say N. 543 544config KALLSYMS_EXTRA_PASS 545 bool "Do an extra kallsyms pass" 546 depends on KALLSYMS 547 help 548 If kallsyms is not working correctly, the build will fail with 549 inconsistent kallsyms data. If that occurs, log a bug report and 550 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 551 Always say N here unless you find a bug in kallsyms, which must be 552 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 553 you wait for kallsyms to be fixed. 554 555 556config HOTPLUG 557 bool "Support for hot-pluggable devices" if EMBEDDED 558 default y 559 help 560 This option is provided for the case where no hotplug or uevent 561 capabilities is wanted by the kernel. You should only consider 562 disabling this option for embedded systems that do not use modules, a 563 dynamic /dev tree, or dynamic device discovery. Just say Y. 564 565config PRINTK 566 default y 567 bool "Enable support for printk" if EMBEDDED 568 help 569 This option enables normal printk support. Removing it 570 eliminates most of the message strings from the kernel image 571 and makes the kernel more or less silent. As this makes it 572 very difficult to diagnose system problems, saying N here is 573 strongly discouraged. 574 575config BUG 576 bool "BUG() support" if EMBEDDED 577 default y 578 help 579 Disabling this option eliminates support for BUG and WARN, reducing 580 the size of your kernel image and potentially quietly ignoring 581 numerous fatal conditions. You should only consider disabling this 582 option for embedded systems with no facilities for reporting errors. 583 Just say Y. 584 585config ELF_CORE 586 default y 587 bool "Enable ELF core dumps" if EMBEDDED 588 help 589 Enable support for generating core dumps. Disabling saves about 4k. 590 591config COMPAT_BRK 592 bool "Disable heap randomization" 593 default y 594 help 595 Randomizing heap placement makes heap exploits harder, but it 596 also breaks ancient binaries (including anything libc5 based). 597 This option changes the bootup default to heap randomization 598 disabled, and can be overriden runtime by setting 599 /proc/sys/kernel/randomize_va_space to 2. 600 601 On non-ancient distros (post-2000 ones) N is usually a safe choice. 602 603config BASE_FULL 604 default y 605 bool "Enable full-sized data structures for core" if EMBEDDED 606 help 607 Disabling this option reduces the size of miscellaneous core 608 kernel data structures. This saves memory on small machines, 609 but may reduce performance. 610 611config FUTEX 612 bool "Enable futex support" if EMBEDDED 613 default y 614 select RT_MUTEXES 615 help 616 Disabling this option will cause the kernel to be built without 617 support for "fast userspace mutexes". The resulting kernel may not 618 run glibc-based applications correctly. 619 620config ANON_INODES 621 bool 622 623config EPOLL 624 bool "Enable eventpoll support" if EMBEDDED 625 default y 626 select ANON_INODES 627 help 628 Disabling this option will cause the kernel to be built without 629 support for epoll family of system calls. 630 631config SIGNALFD 632 bool "Enable signalfd() system call" if EMBEDDED 633 select ANON_INODES 634 default y 635 help 636 Enable the signalfd() system call that allows to receive signals 637 on a file descriptor. 638 639 If unsure, say Y. 640 641config TIMERFD 642 bool "Enable timerfd() system call" if EMBEDDED 643 select ANON_INODES 644 default y 645 help 646 Enable the timerfd() system call that allows to receive timer 647 events on a file descriptor. 648 649 If unsure, say Y. 650 651config EVENTFD 652 bool "Enable eventfd() system call" if EMBEDDED 653 select ANON_INODES 654 default y 655 help 656 Enable the eventfd() system call that allows to receive both 657 kernel notification (ie. KAIO) or userspace notifications. 658 659 If unsure, say Y. 660 661config SHMEM 662 bool "Use full shmem filesystem" if EMBEDDED 663 default y 664 depends on MMU 665 help 666 The shmem is an internal filesystem used to manage shared memory. 667 It is backed by swap and manages resource limits. It is also exported 668 to userspace as tmpfs if TMPFS is enabled. Disabling this 669 option replaces shmem and tmpfs with the much simpler ramfs code, 670 which may be appropriate on small systems without swap. 671 672config VM_EVENT_COUNTERS 673 default y 674 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 675 help 676 VM event counters are needed for event counts to be shown. 677 This option allows the disabling of the VM event counters 678 on EMBEDDED systems. /proc/vmstat will only show page counts 679 if VM event counters are disabled. 680 681config SLUB_DEBUG 682 default y 683 bool "Enable SLUB debugging support" if EMBEDDED 684 depends on SLUB 685 help 686 SLUB has extensive debug support features. Disabling these can 687 result in significant savings in code size. This also disables 688 SLUB sysfs support. /sys/slab will not exist and there will be 689 no support for cache validation etc. 690 691choice 692 prompt "Choose SLAB allocator" 693 default SLUB 694 help 695 This option allows to select a slab allocator. 696 697config SLAB 698 bool "SLAB" 699 help 700 The regular slab allocator that is established and known to work 701 well in all environments. It organizes cache hot objects in 702 per cpu and per node queues. SLAB is the default choice for 703 a slab allocator. 704 705config SLUB 706 bool "SLUB (Unqueued Allocator)" 707 help 708 SLUB is a slab allocator that minimizes cache line usage 709 instead of managing queues of cached objects (SLAB approach). 710 Per cpu caching is realized using slabs of objects instead 711 of queues of objects. SLUB can use memory efficiently 712 and has enhanced diagnostics. 713 714config SLOB 715 depends on EMBEDDED 716 bool "SLOB (Simple Allocator)" 717 help 718 SLOB replaces the stock allocator with a drastically simpler 719 allocator. SLOB is generally more space efficient but 720 does not perform as well on large systems. 721 722endchoice 723 724config PROFILING 725 bool "Profiling support (EXPERIMENTAL)" 726 help 727 Say Y here to enable the extended profiling support mechanisms used 728 by profilers such as OProfile. 729 730config MARKERS 731 bool "Activate markers" 732 help 733 Place an empty function call at each marker site. Can be 734 dynamically changed for a probe function. 735 736source "arch/Kconfig" 737 738config PROC_PAGE_MONITOR 739 default y 740 depends on PROC_FS && MMU 741 bool "Enable /proc page monitoring" if EMBEDDED 742 help 743 Various /proc files exist to monitor process memory utilization: 744 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, 745 /proc/kpagecount, and /proc/kpageflags. Disabling these 746 interfaces will reduce the size of the kernel by approximately 4kb. 747 748endmenu # General setup 749 750config SLABINFO 751 bool 752 depends on PROC_FS 753 depends on SLAB || SLUB 754 default y 755 756config RT_MUTEXES 757 boolean 758 select PLIST 759 760config TINY_SHMEM 761 default !SHMEM 762 bool 763 764config BASE_SMALL 765 int 766 default 0 if BASE_FULL 767 default 1 if !BASE_FULL 768 769menuconfig MODULES 770 bool "Enable loadable module support" 771 help 772 Kernel modules are small pieces of compiled code which can 773 be inserted in the running kernel, rather than being 774 permanently built into the kernel. You use the "modprobe" 775 tool to add (and sometimes remove) them. If you say Y here, 776 many parts of the kernel can be built as modules (by 777 answering M instead of Y where indicated): this is most 778 useful for infrequently used options which are not required 779 for booting. For more information, see the man pages for 780 modprobe, lsmod, modinfo, insmod and rmmod. 781 782 If you say Y here, you will need to run "make 783 modules_install" to put the modules under /lib/modules/ 784 where modprobe can find them (you may need to be root to do 785 this). 786 787 If unsure, say Y. 788 789config MODULE_UNLOAD 790 bool "Module unloading" 791 depends on MODULES 792 help 793 Without this option you will not be able to unload any 794 modules (note that some modules may not be unloadable 795 anyway), which makes your kernel slightly smaller and 796 simpler. If unsure, say Y. 797 798config MODULE_FORCE_UNLOAD 799 bool "Forced module unloading" 800 depends on MODULE_UNLOAD && EXPERIMENTAL 801 help 802 This option allows you to force a module to unload, even if the 803 kernel believes it is unsafe: the kernel will remove the module 804 without waiting for anyone to stop using it (using the -f option to 805 rmmod). This is mainly for kernel developers and desperate users. 806 If unsure, say N. 807 808config MODVERSIONS 809 bool "Module versioning support" 810 depends on MODULES 811 help 812 Usually, you have to use modules compiled with your kernel. 813 Saying Y here makes it sometimes possible to use modules 814 compiled for different kernels, by adding enough information 815 to the modules to (hopefully) spot any changes which would 816 make them incompatible with the kernel you are running. If 817 unsure, say N. 818 819config MODULE_SRCVERSION_ALL 820 bool "Source checksum for all modules" 821 depends on MODULES 822 help 823 Modules which contain a MODULE_VERSION get an extra "srcversion" 824 field inserted into their modinfo section, which contains a 825 sum of the source files which made it. This helps maintainers 826 see exactly which source was used to build a module (since 827 others sometimes change the module source without updating 828 the version). With this option, such a "srcversion" field 829 will be created for all modules. If unsure, say N. 830 831config KMOD 832 bool "Automatic kernel module loading" 833 depends on MODULES 834 help 835 Normally when you have selected some parts of the kernel to 836 be created as kernel modules, you must load them (using the 837 "modprobe" command) before you can use them. If you say Y 838 here, some parts of the kernel will be able to load modules 839 automatically: when a part of the kernel needs a module, it 840 runs modprobe with the appropriate arguments, thereby 841 loading the module if it is available. If unsure, say Y. 842 843config STOP_MACHINE 844 bool 845 default y 846 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 847 help 848 Need stop_machine() primitive. 849 850source "block/Kconfig" 851 852config PREEMPT_NOTIFIERS 853 bool 854 855choice 856 prompt "RCU implementation type:" 857 default CLASSIC_RCU 858 help 859 This allows you to choose either the classic RCU implementation 860 that is designed for best read-side performance on non-realtime 861 systems, or the preemptible RCU implementation for best latency 862 on realtime systems. Note that some kernel preemption modes 863 will restrict your choice. 864 865 Select the default if you are unsure. 866 867config CLASSIC_RCU 868 bool "Classic RCU" 869 help 870 This option selects the classic RCU implementation that is 871 designed for best read-side performance on non-realtime 872 systems. 873 874 Say Y if you are unsure. 875 876config PREEMPT_RCU 877 bool "Preemptible RCU" 878 depends on PREEMPT 879 help 880 This option reduces the latency of the kernel by making certain 881 RCU sections preemptible. Normally RCU code is non-preemptible, if 882 this option is selected then read-only RCU sections become 883 preemptible. This helps latency, but may expose bugs due to 884 now-naive assumptions about each RCU read-side critical section 885 remaining on a given CPU through its execution. 886 887 Say N if you are unsure. 888 889endchoice 890