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 "$ARCH_DEFCONFIG" 17 default "arch/$ARCH/defconfig" 18 19menu "General setup" 20 21config EXPERIMENTAL 22 bool "Prompt for development and/or incomplete code/drivers" 23 ---help--- 24 Some of the various things that Linux supports (such as network 25 drivers, file systems, network protocols, etc.) can be in a state 26 of development where the functionality, stability, or the level of 27 testing is not yet high enough for general use. This is usually 28 known as the "alpha-test" phase among developers. If a feature is 29 currently in alpha-test, then the developers usually discourage 30 uninformed widespread use of this feature by the general public to 31 avoid "Why doesn't this work?" type mail messages. However, active 32 testing and use of these systems is welcomed. Just be aware that it 33 may not meet the normal level of reliability or it may fail to work 34 in some special cases. Detailed bug reports from people familiar 35 with the kernel internals are usually welcomed by the developers 36 (before submitting bug reports, please read the documents 37 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 38 <file:Documentation/BUG-HUNTING>, and 39 <file:Documentation/oops-tracing.txt> in the kernel source). 40 41 This option will also make obsoleted drivers available. These are 42 drivers that have been replaced by something else, and/or are 43 scheduled to be removed in a future kernel release. 44 45 Unless you intend to help test and develop a feature or driver that 46 falls into this category, or you have a situation that requires 47 using these features, you should probably say N here, which will 48 cause the configurator to present you with fewer choices. If 49 you say Y here, you will be offered the choice of using features or 50 drivers that are currently considered to be in the alpha-test phase. 51 52config BROKEN 53 bool 54 55config BROKEN_ON_SMP 56 bool 57 depends on BROKEN || !SMP 58 default y 59 60config LOCK_KERNEL 61 bool 62 depends on SMP || PREEMPT 63 default y 64 65config INIT_ENV_ARG_LIMIT 66 int 67 default 32 if !UML 68 default 128 if UML 69 help 70 Maximum of each of the number of arguments and environment 71 variables passed to init from the kernel command line. 72 73 74config LOCALVERSION 75 string "Local version - append to kernel release" 76 help 77 Append an extra string to the end of your kernel version. 78 This will show up when you type uname, for example. 79 The string you set here will be appended after the contents of 80 any files with a filename matching localversion* in your 81 object and source tree, in that order. Your total string can 82 be a maximum of 64 characters. 83 84config LOCALVERSION_AUTO 85 bool "Automatically append version information to the version string" 86 default y 87 help 88 This will try to automatically determine if the current tree is a 89 release tree by looking for git tags that belong to the current 90 top of tree revision. 91 92 A string of the format -gxxxxxxxx will be added to the localversion 93 if a git-based tree is found. The string generated by this will be 94 appended after any matching localversion* files, and after the value 95 set in CONFIG_LOCALVERSION. 96 97 (The actual string used here is the first eight characters produced 98 by running the command: 99 100 $ git rev-parse --verify HEAD 101 102 which is done within the script "scripts/setlocalversion".) 103 104config SWAP 105 bool "Support for paging of anonymous memory (swap)" 106 depends on MMU && BLOCK 107 default y 108 help 109 This option allows you to choose whether you want to have support 110 for so called swap devices or swap files in your kernel that are 111 used to provide more virtual memory than the actual RAM present 112 in your computer. If unsure say Y. 113 114config SYSVIPC 115 bool "System V IPC" 116 ---help--- 117 Inter Process Communication is a suite of library functions and 118 system calls which let processes (running programs) synchronize and 119 exchange information. It is generally considered to be a good thing, 120 and some programs won't run unless you say Y here. In particular, if 121 you want to run the DOS emulator dosemu under Linux (read the 122 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 123 you'll need to say Y here. 124 125 You can find documentation about IPC with "info ipc" and also in 126 section 6.4 of the Linux Programmer's Guide, available from 127 <http://www.tldp.org/guides.html>. 128 129config SYSVIPC_SYSCTL 130 bool 131 depends on SYSVIPC 132 depends on SYSCTL 133 default y 134 135config POSIX_MQUEUE 136 bool "POSIX Message Queues" 137 depends on NET && EXPERIMENTAL 138 ---help--- 139 POSIX variant of message queues is a part of IPC. In POSIX message 140 queues every message has a priority which decides about succession 141 of receiving it by a process. If you want to compile and run 142 programs written e.g. for Solaris with use of its POSIX message 143 queues (functions mq_*) say Y here. 144 145 POSIX message queues are visible as a filesystem called 'mqueue' 146 and can be mounted somewhere if you want to do filesystem 147 operations on message queues. 148 149 If unsure, say Y. 150 151config BSD_PROCESS_ACCT 152 bool "BSD Process Accounting" 153 help 154 If you say Y here, a user level program will be able to instruct the 155 kernel (via a special system call) to write process accounting 156 information to a file: whenever a process exits, information about 157 that process will be appended to the file by the kernel. The 158 information includes things such as creation time, owning user, 159 command name, memory usage, controlling terminal etc. (the complete 160 list is in the struct acct in <file:include/linux/acct.h>). It is 161 up to the user level program to do useful things with this 162 information. This is generally a good idea, so say Y. 163 164config BSD_PROCESS_ACCT_V3 165 bool "BSD Process Accounting version 3 file format" 166 depends on BSD_PROCESS_ACCT 167 default n 168 help 169 If you say Y here, the process accounting information is written 170 in a new file format that also logs the process IDs of each 171 process and it's parent. Note that this file format is incompatible 172 with previous v0/v1/v2 file formats, so you will need updated tools 173 for processing it. A preliminary version of these tools is available 174 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 175 176config TASKSTATS 177 bool "Export task/process statistics through netlink (EXPERIMENTAL)" 178 depends on NET 179 default n 180 help 181 Export selected statistics for tasks/processes through the 182 generic netlink interface. Unlike BSD process accounting, the 183 statistics are available during the lifetime of tasks/processes as 184 responses to commands. Like BSD accounting, they are sent to user 185 space on task exit. 186 187 Say N if unsure. 188 189config TASK_DELAY_ACCT 190 bool "Enable per-task delay accounting (EXPERIMENTAL)" 191 depends on TASKSTATS 192 help 193 Collect information on time spent by a task waiting for system 194 resources like cpu, synchronous block I/O completion and swapping 195 in pages. Such statistics can help in setting a task's priorities 196 relative to other tasks for cpu, io, rss limits etc. 197 198 Say N if unsure. 199 200config TASK_XACCT 201 bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 202 depends on TASKSTATS 203 help 204 Collect extended task accounting data and send the data 205 to userland for processing over the taskstats interface. 206 207 Say N if unsure. 208 209config TASK_IO_ACCOUNTING 210 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 211 depends on TASK_XACCT 212 help 213 Collect information on the number of bytes of storage I/O which this 214 task has caused. 215 216 Say N if unsure. 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|| SUPERH) 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 AUDIT_TREE 238 def_bool y 239 depends on AUDITSYSCALL && INOTIFY 240 241config IKCONFIG 242 tristate "Kernel .config support" 243 ---help--- 244 This option enables the complete Linux kernel ".config" file 245 contents to be saved in the kernel. It provides documentation 246 of which kernel options are used in a running kernel or in an 247 on-disk kernel. This information can be extracted from the kernel 248 image file with the script scripts/extract-ikconfig and used as 249 input to rebuild the current kernel or to build another kernel. 250 It can also be extracted from a running kernel by reading 251 /proc/config.gz if enabled (below). 252 253config IKCONFIG_PROC 254 bool "Enable access to .config through /proc/config.gz" 255 depends on IKCONFIG && PROC_FS 256 ---help--- 257 This option enables access to the kernel configuration file 258 through /proc/config.gz. 259 260config LOG_BUF_SHIFT 261 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 262 range 12 21 263 default 17 264 help 265 Select kernel log buffer size as a power of 2. 266 Examples: 267 17 => 128 KB 268 16 => 64 KB 269 15 => 32 KB 270 14 => 16 KB 271 13 => 8 KB 272 12 => 4 KB 273 274config CGROUPS 275 bool "Control Group support" 276 help 277 This option will let you use process cgroup subsystems 278 such as Cpusets 279 280 Say N if unsure. 281 282config CGROUP_DEBUG 283 bool "Example debug cgroup subsystem" 284 depends on CGROUPS 285 default n 286 help 287 This option enables a simple cgroup subsystem that 288 exports useful debugging information about the cgroups 289 framework 290 291 Say N if unsure 292 293config CGROUP_NS 294 bool "Namespace cgroup subsystem" 295 depends on CGROUPS 296 help 297 Provides a simple namespace cgroup subsystem to 298 provide hierarchical naming of sets of namespaces, 299 for instance virtual servers and checkpoint/restart 300 jobs. 301 302config CGROUP_DEVICE 303 bool "Device controller for cgroups" 304 depends on CGROUPS && EXPERIMENTAL 305 help 306 Provides a cgroup implementing whitelists for devices which 307 a process in the cgroup can mknod or open. 308 309config CPUSETS 310 bool "Cpuset support" 311 depends on SMP && CGROUPS 312 help 313 This option will let you create and manage CPUSETs which 314 allow dynamically partitioning a system into sets of CPUs and 315 Memory Nodes and assigning tasks to run only within those sets. 316 This is primarily useful on large SMP or NUMA systems. 317 318 Say N if unsure. 319 320# 321# Architectures with an unreliable sched_clock() should select this: 322# 323config HAVE_UNSTABLE_SCHED_CLOCK 324 bool 325 326config GROUP_SCHED 327 bool "Group CPU scheduler" 328 depends on EXPERIMENTAL 329 default n 330 help 331 This feature lets CPU scheduler recognize task groups and control CPU 332 bandwidth allocation to such task groups. 333 334config FAIR_GROUP_SCHED 335 bool "Group scheduling for SCHED_OTHER" 336 depends on GROUP_SCHED 337 default GROUP_SCHED 338 339config RT_GROUP_SCHED 340 bool "Group scheduling for SCHED_RR/FIFO" 341 depends on EXPERIMENTAL 342 depends on GROUP_SCHED 343 default n 344 help 345 This feature lets you explicitly allocate real CPU bandwidth 346 to users or control groups (depending on the "Basis for grouping tasks" 347 setting below. If enabled, it will also make it impossible to 348 schedule realtime tasks for non-root users until you allocate 349 realtime bandwidth for them. 350 See Documentation/sched-rt-group.txt for more information. 351 352choice 353 depends on GROUP_SCHED 354 prompt "Basis for grouping tasks" 355 default USER_SCHED 356 357config USER_SCHED 358 bool "user id" 359 help 360 This option will choose userid as the basis for grouping 361 tasks, thus providing equal CPU bandwidth to each user. 362 363config CGROUP_SCHED 364 bool "Control groups" 365 depends on CGROUPS 366 help 367 This option allows you to create arbitrary task groups 368 using the "cgroup" pseudo filesystem and control 369 the cpu bandwidth allocated to each such task group. 370 Refer to Documentation/cgroups.txt for more information 371 on "cgroup" pseudo filesystem. 372 373endchoice 374 375config CGROUP_CPUACCT 376 bool "Simple CPU accounting cgroup subsystem" 377 depends on CGROUPS 378 help 379 Provides a simple Resource Controller for monitoring the 380 total CPU consumed by the tasks in a cgroup 381 382config RESOURCE_COUNTERS 383 bool "Resource counters" 384 help 385 This option enables controller independent resource accounting 386 infrastructure that works with cgroups 387 depends on CGROUPS 388 389config MM_OWNER 390 bool 391 392config CGROUP_MEM_RES_CTLR 393 bool "Memory Resource Controller for Control Groups" 394 depends on CGROUPS && RESOURCE_COUNTERS 395 select MM_OWNER 396 help 397 Provides a memory resource controller that manages both page cache and 398 RSS memory. 399 400 Note that setting this option increases fixed memory overhead 401 associated with each page of memory in the system by 4/8 bytes 402 and also increases cache misses because struct page on many 64bit 403 systems will not fit into a single cache line anymore. 404 405 Only enable when you're ok with these trade offs and really 406 sure you need the memory resource controller. 407 408 This config option also selects MM_OWNER config option, which 409 could in turn add some fork/exit overhead. 410 411config SYSFS_DEPRECATED 412 bool 413 414config SYSFS_DEPRECATED_V2 415 bool "Create deprecated sysfs files" 416 depends on SYSFS 417 default y 418 select SYSFS_DEPRECATED 419 help 420 This option creates deprecated symlinks such as the 421 "device"-link, the <subsystem>:<name>-link, and the 422 "bus"-link. It may also add deprecated key in the 423 uevent environment. 424 None of these features or values should be used today, as 425 they export driver core implementation details to userspace 426 or export properties which can't be kept stable across kernel 427 releases. 428 429 If enabled, this option will also move any device structures 430 that belong to a class, back into the /sys/class hierarchy, in 431 order to support older versions of udev and some userspace 432 programs. 433 434 If you are using a distro with the most recent userspace 435 packages, it should be safe to say N here. 436 437config PROC_PID_CPUSET 438 bool "Include legacy /proc/<pid>/cpuset file" 439 depends on CPUSETS 440 default y 441 442config RELAY 443 bool "Kernel->user space relay support (formerly relayfs)" 444 help 445 This option enables support for relay interface support in 446 certain file systems (such as debugfs). 447 It is designed to provide an efficient mechanism for tools and 448 facilities to relay large amounts of data from kernel space to 449 user space. 450 451 If unsure, say N. 452 453config NAMESPACES 454 bool "Namespaces support" if EMBEDDED 455 default !EMBEDDED 456 help 457 Provides the way to make tasks work with different objects using 458 the same id. For example same IPC id may refer to different objects 459 or same user id or pid may refer to different tasks when used in 460 different namespaces. 461 462config UTS_NS 463 bool "UTS namespace" 464 depends on NAMESPACES 465 help 466 In this namespace tasks see different info provided with the 467 uname() system call 468 469config IPC_NS 470 bool "IPC namespace" 471 depends on NAMESPACES && SYSVIPC 472 help 473 In this namespace tasks work with IPC ids which correspond to 474 different IPC objects in different namespaces 475 476config USER_NS 477 bool "User namespace (EXPERIMENTAL)" 478 depends on NAMESPACES && EXPERIMENTAL 479 help 480 This allows containers, i.e. vservers, to use user namespaces 481 to provide different user info for different servers. 482 If unsure, say N. 483 484config PID_NS 485 bool "PID Namespaces (EXPERIMENTAL)" 486 default n 487 depends on NAMESPACES && EXPERIMENTAL 488 help 489 Suport process id namespaces. This allows having multiple 490 process with the same pid as long as they are in different 491 pid namespaces. This is a building block of containers. 492 493 Unless you want to work with an experimental feature 494 say N here. 495 496config BLK_DEV_INITRD 497 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 498 depends on BROKEN || !FRV 499 help 500 The initial RAM filesystem is a ramfs which is loaded by the 501 boot loader (loadlin or lilo) and that is mounted as root 502 before the normal boot procedure. It is typically used to 503 load modules needed to mount the "real" root file system, 504 etc. See <file:Documentation/initrd.txt> for details. 505 506 If RAM disk support (BLK_DEV_RAM) is also included, this 507 also enables initial RAM disk (initrd) support and adds 508 15 Kbytes (more on some other architectures) to the kernel size. 509 510 If unsure say Y. 511 512if BLK_DEV_INITRD 513 514source "usr/Kconfig" 515 516endif 517 518config CC_OPTIMIZE_FOR_SIZE 519 bool "Optimize for size" 520 default y 521 help 522 Enabling this option will pass "-Os" instead of "-O2" to gcc 523 resulting in a smaller kernel. 524 525 If unsure, say N. 526 527config SYSCTL 528 bool 529 530menuconfig EMBEDDED 531 bool "Configure standard kernel features (for small systems)" 532 help 533 This option allows certain base kernel options and settings 534 to be disabled or tweaked. This is for specialized 535 environments which can tolerate a "non-standard" kernel. 536 Only use this if you really know what you are doing. 537 538config UID16 539 bool "Enable 16-bit UID system calls" if EMBEDDED 540 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 541 default y 542 help 543 This enables the legacy 16-bit UID syscall wrappers. 544 545config SYSCTL_SYSCALL 546 bool "Sysctl syscall support" if EMBEDDED 547 default y 548 select SYSCTL 549 ---help--- 550 sys_sysctl uses binary paths that have been found challenging 551 to properly maintain and use. The interface in /proc/sys 552 using paths with ascii names is now the primary path to this 553 information. 554 555 Almost nothing using the binary sysctl interface so if you are 556 trying to save some space it is probably safe to disable this, 557 making your kernel marginally smaller. 558 559 If unsure say Y here. 560 561config SYSCTL_SYSCALL_CHECK 562 bool "Sysctl checks" if EMBEDDED 563 depends on SYSCTL_SYSCALL 564 default y 565 ---help--- 566 sys_sysctl uses binary paths that have been found challenging 567 to properly maintain and use. This enables checks that help 568 you to keep things correct. 569 570 If unsure say Y here. 571 572config KALLSYMS 573 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 574 default y 575 help 576 Say Y here to let the kernel print out symbolic crash information and 577 symbolic stack backtraces. This increases the size of the kernel 578 somewhat, as all symbols have to be loaded into the kernel image. 579 580config KALLSYMS_ALL 581 bool "Include all symbols in kallsyms" 582 depends on DEBUG_KERNEL && KALLSYMS 583 help 584 Normally kallsyms only contains the symbols of functions, for nicer 585 OOPS messages. Some debuggers can use kallsyms for other 586 symbols too: say Y here to include all symbols, if you need them 587 and you don't care about adding 300k to the size of your kernel. 588 589 Say N. 590 591config KALLSYMS_EXTRA_PASS 592 bool "Do an extra kallsyms pass" 593 depends on KALLSYMS 594 help 595 If kallsyms is not working correctly, the build will fail with 596 inconsistent kallsyms data. If that occurs, log a bug report and 597 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 598 Always say N here unless you find a bug in kallsyms, which must be 599 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 600 you wait for kallsyms to be fixed. 601 602 603config HOTPLUG 604 bool "Support for hot-pluggable devices" if EMBEDDED 605 default y 606 help 607 This option is provided for the case where no hotplug or uevent 608 capabilities is wanted by the kernel. You should only consider 609 disabling this option for embedded systems that do not use modules, a 610 dynamic /dev tree, or dynamic device discovery. Just say Y. 611 612config PRINTK 613 default y 614 bool "Enable support for printk" if EMBEDDED 615 help 616 This option enables normal printk support. Removing it 617 eliminates most of the message strings from the kernel image 618 and makes the kernel more or less silent. As this makes it 619 very difficult to diagnose system problems, saying N here is 620 strongly discouraged. 621 622config BUG 623 bool "BUG() support" if EMBEDDED 624 default y 625 help 626 Disabling this option eliminates support for BUG and WARN, reducing 627 the size of your kernel image and potentially quietly ignoring 628 numerous fatal conditions. You should only consider disabling this 629 option for embedded systems with no facilities for reporting errors. 630 Just say Y. 631 632config ELF_CORE 633 default y 634 bool "Enable ELF core dumps" if EMBEDDED 635 help 636 Enable support for generating core dumps. Disabling saves about 4k. 637 638config PCSPKR_PLATFORM 639 bool "Enable PC-Speaker support" if EMBEDDED 640 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES 641 default y 642 help 643 This option allows to disable the internal PC-Speaker 644 support, saving some memory. 645 646config COMPAT_BRK 647 bool "Disable heap randomization" 648 default y 649 help 650 Randomizing heap placement makes heap exploits harder, but it 651 also breaks ancient binaries (including anything libc5 based). 652 This option changes the bootup default to heap randomization 653 disabled, and can be overriden runtime by setting 654 /proc/sys/kernel/randomize_va_space to 2. 655 656 On non-ancient distros (post-2000 ones) N is usually a safe choice. 657 658config BASE_FULL 659 default y 660 bool "Enable full-sized data structures for core" if EMBEDDED 661 help 662 Disabling this option reduces the size of miscellaneous core 663 kernel data structures. This saves memory on small machines, 664 but may reduce performance. 665 666config FUTEX 667 bool "Enable futex support" if EMBEDDED 668 default y 669 select RT_MUTEXES 670 help 671 Disabling this option will cause the kernel to be built without 672 support for "fast userspace mutexes". The resulting kernel may not 673 run glibc-based applications correctly. 674 675config ANON_INODES 676 bool 677 678config EPOLL 679 bool "Enable eventpoll support" if EMBEDDED 680 default y 681 select ANON_INODES 682 help 683 Disabling this option will cause the kernel to be built without 684 support for epoll family of system calls. 685 686config SIGNALFD 687 bool "Enable signalfd() system call" if EMBEDDED 688 select ANON_INODES 689 default y 690 help 691 Enable the signalfd() system call that allows to receive signals 692 on a file descriptor. 693 694 If unsure, say Y. 695 696config TIMERFD 697 bool "Enable timerfd() system call" if EMBEDDED 698 select ANON_INODES 699 default y 700 help 701 Enable the timerfd() system call that allows to receive timer 702 events on a file descriptor. 703 704 If unsure, say Y. 705 706config EVENTFD 707 bool "Enable eventfd() system call" if EMBEDDED 708 select ANON_INODES 709 default y 710 help 711 Enable the eventfd() system call that allows to receive both 712 kernel notification (ie. KAIO) or userspace notifications. 713 714 If unsure, say Y. 715 716config SHMEM 717 bool "Use full shmem filesystem" if EMBEDDED 718 default y 719 depends on MMU 720 help 721 The shmem is an internal filesystem used to manage shared memory. 722 It is backed by swap and manages resource limits. It is also exported 723 to userspace as tmpfs if TMPFS is enabled. Disabling this 724 option replaces shmem and tmpfs with the much simpler ramfs code, 725 which may be appropriate on small systems without swap. 726 727config VM_EVENT_COUNTERS 728 default y 729 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 730 help 731 VM event counters are needed for event counts to be shown. 732 This option allows the disabling of the VM event counters 733 on EMBEDDED systems. /proc/vmstat will only show page counts 734 if VM event counters are disabled. 735 736config SLUB_DEBUG 737 default y 738 bool "Enable SLUB debugging support" if EMBEDDED 739 depends on SLUB && SYSFS 740 help 741 SLUB has extensive debug support features. Disabling these can 742 result in significant savings in code size. This also disables 743 SLUB sysfs support. /sys/slab will not exist and there will be 744 no support for cache validation etc. 745 746choice 747 prompt "Choose SLAB allocator" 748 default SLUB 749 help 750 This option allows to select a slab allocator. 751 752config SLAB 753 bool "SLAB" 754 help 755 The regular slab allocator that is established and known to work 756 well in all environments. It organizes cache hot objects in 757 per cpu and per node queues. SLAB is the default choice for 758 a slab allocator. 759 760config SLUB 761 bool "SLUB (Unqueued Allocator)" 762 help 763 SLUB is a slab allocator that minimizes cache line usage 764 instead of managing queues of cached objects (SLAB approach). 765 Per cpu caching is realized using slabs of objects instead 766 of queues of objects. SLUB can use memory efficiently 767 and has enhanced diagnostics. 768 769config SLOB 770 depends on EMBEDDED 771 bool "SLOB (Simple Allocator)" 772 help 773 SLOB replaces the stock allocator with a drastically simpler 774 allocator. SLOB is generally more space efficient but 775 does not perform as well on large systems. 776 777endchoice 778 779config PROFILING 780 bool "Profiling support (EXPERIMENTAL)" 781 help 782 Say Y here to enable the extended profiling support mechanisms used 783 by profilers such as OProfile. 784 785config MARKERS 786 bool "Activate markers" 787 help 788 Place an empty function call at each marker site. Can be 789 dynamically changed for a probe function. 790 791source "arch/Kconfig" 792 793config PROC_PAGE_MONITOR 794 default y 795 depends on PROC_FS && MMU 796 bool "Enable /proc page monitoring" if EMBEDDED 797 help 798 Various /proc files exist to monitor process memory utilization: 799 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, 800 /proc/kpagecount, and /proc/kpageflags. Disabling these 801 interfaces will reduce the size of the kernel by approximately 4kb. 802 803endmenu # General setup 804 805config SLABINFO 806 bool 807 depends on PROC_FS 808 depends on SLAB || SLUB_DEBUG 809 default y 810 811config RT_MUTEXES 812 boolean 813 select PLIST 814 815config TINY_SHMEM 816 default !SHMEM 817 bool 818 819config BASE_SMALL 820 int 821 default 0 if BASE_FULL 822 default 1 if !BASE_FULL 823 824menuconfig MODULES 825 bool "Enable loadable module support" 826 help 827 Kernel modules are small pieces of compiled code which can 828 be inserted in the running kernel, rather than being 829 permanently built into the kernel. You use the "modprobe" 830 tool to add (and sometimes remove) them. If you say Y here, 831 many parts of the kernel can be built as modules (by 832 answering M instead of Y where indicated): this is most 833 useful for infrequently used options which are not required 834 for booting. For more information, see the man pages for 835 modprobe, lsmod, modinfo, insmod and rmmod. 836 837 If you say Y here, you will need to run "make 838 modules_install" to put the modules under /lib/modules/ 839 where modprobe can find them (you may need to be root to do 840 this). 841 842 If unsure, say Y. 843 844config MODULE_FORCE_LOAD 845 bool "Forced module loading" 846 depends on MODULES 847 default n 848 help 849 Allow loading of modules without version information (ie. modprobe 850 --force). Forced module loading sets the 'F' (forced) taint flag and 851 is usually a really bad idea. 852 853config MODULE_UNLOAD 854 bool "Module unloading" 855 depends on MODULES 856 help 857 Without this option you will not be able to unload any 858 modules (note that some modules may not be unloadable 859 anyway), which makes your kernel slightly smaller and 860 simpler. If unsure, say Y. 861 862config MODULE_FORCE_UNLOAD 863 bool "Forced module unloading" 864 depends on MODULE_UNLOAD && EXPERIMENTAL 865 help 866 This option allows you to force a module to unload, even if the 867 kernel believes it is unsafe: the kernel will remove the module 868 without waiting for anyone to stop using it (using the -f option to 869 rmmod). This is mainly for kernel developers and desperate users. 870 If unsure, say N. 871 872config MODVERSIONS 873 bool "Module versioning support" 874 depends on MODULES 875 help 876 Usually, you have to use modules compiled with your kernel. 877 Saying Y here makes it sometimes possible to use modules 878 compiled for different kernels, by adding enough information 879 to the modules to (hopefully) spot any changes which would 880 make them incompatible with the kernel you are running. If 881 unsure, say N. 882 883config MODULE_SRCVERSION_ALL 884 bool "Source checksum for all modules" 885 depends on MODULES 886 help 887 Modules which contain a MODULE_VERSION get an extra "srcversion" 888 field inserted into their modinfo section, which contains a 889 sum of the source files which made it. This helps maintainers 890 see exactly which source was used to build a module (since 891 others sometimes change the module source without updating 892 the version). With this option, such a "srcversion" field 893 will be created for all modules. If unsure, say N. 894 895config KMOD 896 bool "Automatic kernel module loading" 897 depends on MODULES 898 help 899 Normally when you have selected some parts of the kernel to 900 be created as kernel modules, you must load them (using the 901 "modprobe" command) before you can use them. If you say Y 902 here, some parts of the kernel will be able to load modules 903 automatically: when a part of the kernel needs a module, it 904 runs modprobe with the appropriate arguments, thereby 905 loading the module if it is available. If unsure, say Y. 906 907config STOP_MACHINE 908 bool 909 default y 910 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 911 help 912 Need stop_machine() primitive. 913 914source "block/Kconfig" 915 916config PREEMPT_NOTIFIERS 917 bool 918 919config CLASSIC_RCU 920 def_bool !PREEMPT_RCU 921 help 922 This option selects the classic RCU implementation that is 923 designed for best read-side performance on non-realtime 924 systems. Classic RCU is the default. Note that the 925 PREEMPT_RCU symbol is used to select/deselect this option. 926