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 These are 41 drivers that have been replaced by something else, and/or are 42 scheduled to be removed in a future kernel release. 43 44 Unless you intend to help test and develop a feature or driver that 45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 17 263 help 264 Select kernel log buffer size as a power of 2. 265 Examples: 266 17 => 128 KB 267 16 => 64 KB 268 15 => 32 KB 269 14 => 16 KB 270 13 => 8 KB 271 12 => 4 KB 272 273config CGROUPS 274 bool "Control Group support" 275 help 276 This option will let you use process cgroup subsystems 277 such as Cpusets 278 279 Say N if unsure. 280 281config CGROUP_DEBUG 282 bool "Example debug cgroup subsystem" 283 depends on CGROUPS 284 default n 285 help 286 This option enables a simple cgroup subsystem that 287 exports useful debugging information about the cgroups 288 framework 289 290 Say N if unsure 291 292config CGROUP_NS 293 bool "Namespace cgroup subsystem" 294 depends on CGROUPS 295 help 296 Provides a simple namespace cgroup subsystem to 297 provide hierarchical naming of sets of namespaces, 298 for instance virtual servers and checkpoint/restart 299 jobs. 300 301config CGROUP_DEVICE 302 bool "Device controller for cgroups" 303 depends on CGROUPS && EXPERIMENTAL 304 help 305 Provides a cgroup implementing whitelists for devices which 306 a process in the cgroup can mknod or open. 307 308config CPUSETS 309 bool "Cpuset support" 310 depends on SMP && CGROUPS 311 help 312 This option will let you create and manage CPUSETs which 313 allow dynamically partitioning a system into sets of CPUs and 314 Memory Nodes and assigning tasks to run only within those sets. 315 This is primarily useful on large SMP or NUMA systems. 316 317 Say N if unsure. 318 319config GROUP_SCHED 320 bool "Group CPU scheduler" 321 default y 322 help 323 This feature lets CPU scheduler recognize task groups and control CPU 324 bandwidth allocation to such task groups. 325 326config FAIR_GROUP_SCHED 327 bool "Group scheduling for SCHED_OTHER" 328 depends on GROUP_SCHED 329 default y 330 331config RT_GROUP_SCHED 332 bool "Group scheduling for SCHED_RR/FIFO" 333 depends on EXPERIMENTAL 334 depends on GROUP_SCHED 335 default n 336 help 337 This feature lets you explicitly allocate real CPU bandwidth 338 to users or control groups (depending on the "Basis for grouping tasks" 339 setting below. If enabled, it will also make it impossible to 340 schedule realtime tasks for non-root users until you allocate 341 realtime bandwidth for them. 342 See Documentation/sched-rt-group.txt for more information. 343 344choice 345 depends on GROUP_SCHED 346 prompt "Basis for grouping tasks" 347 default USER_SCHED 348 349config USER_SCHED 350 bool "user id" 351 help 352 This option will choose userid as the basis for grouping 353 tasks, thus providing equal CPU bandwidth to each user. 354 355config CGROUP_SCHED 356 bool "Control groups" 357 depends on CGROUPS 358 help 359 This option allows you to create arbitrary task groups 360 using the "cgroup" pseudo filesystem and control 361 the cpu bandwidth allocated to each such task group. 362 Refer to Documentation/cgroups.txt for more information 363 on "cgroup" pseudo filesystem. 364 365endchoice 366 367config CGROUP_CPUACCT 368 bool "Simple CPU accounting cgroup subsystem" 369 depends on CGROUPS 370 help 371 Provides a simple Resource Controller for monitoring the 372 total CPU consumed by the tasks in a cgroup 373 374config RESOURCE_COUNTERS 375 bool "Resource counters" 376 help 377 This option enables controller independent resource accounting 378 infrastructure that works with cgroups 379 depends on CGROUPS 380 381config MM_OWNER 382 bool 383 384config CGROUP_MEM_RES_CTLR 385 bool "Memory Resource Controller for Control Groups" 386 depends on CGROUPS && RESOURCE_COUNTERS 387 select MM_OWNER 388 help 389 Provides a memory resource controller that manages both page cache and 390 RSS memory. 391 392 Note that setting this option increases fixed memory overhead 393 associated with each page of memory in the system by 4/8 bytes 394 and also increases cache misses because struct page on many 64bit 395 systems will not fit into a single cache line anymore. 396 397 Only enable when you're ok with these trade offs and really 398 sure you need the memory resource controller. 399 400 This config option also selects MM_OWNER config option, which 401 could in turn add some fork/exit overhead. 402 403config SYSFS_DEPRECATED 404 bool 405 406config SYSFS_DEPRECATED_V2 407 bool "Create deprecated sysfs files" 408 depends on SYSFS 409 default y 410 select SYSFS_DEPRECATED 411 help 412 This option creates deprecated symlinks such as the 413 "device"-link, the <subsystem>:<name>-link, and the 414 "bus"-link. It may also add deprecated key in the 415 uevent environment. 416 None of these features or values should be used today, as 417 they export driver core implementation details to userspace 418 or export properties which can't be kept stable across kernel 419 releases. 420 421 If enabled, this option will also move any device structures 422 that belong to a class, back into the /sys/class hierarchy, in 423 order to support older versions of udev and some userspace 424 programs. 425 426 If you are using a distro with the most recent userspace 427 packages, it should be safe to say N here. 428 429config PROC_PID_CPUSET 430 bool "Include legacy /proc/<pid>/cpuset file" 431 depends on CPUSETS 432 default y 433 434config RELAY 435 bool "Kernel->user space relay support (formerly relayfs)" 436 help 437 This option enables support for relay interface support in 438 certain file systems (such as debugfs). 439 It is designed to provide an efficient mechanism for tools and 440 facilities to relay large amounts of data from kernel space to 441 user space. 442 443 If unsure, say N. 444 445config NAMESPACES 446 bool "Namespaces support" if EMBEDDED 447 default !EMBEDDED 448 help 449 Provides the way to make tasks work with different objects using 450 the same id. For example same IPC id may refer to different objects 451 or same user id or pid may refer to different tasks when used in 452 different namespaces. 453 454config UTS_NS 455 bool "UTS namespace" 456 depends on NAMESPACES 457 help 458 In this namespace tasks see different info provided with the 459 uname() system call 460 461config IPC_NS 462 bool "IPC namespace" 463 depends on NAMESPACES && SYSVIPC 464 help 465 In this namespace tasks work with IPC ids which correspond to 466 different IPC objects in different namespaces 467 468config USER_NS 469 bool "User namespace (EXPERIMENTAL)" 470 depends on NAMESPACES && EXPERIMENTAL 471 help 472 This allows containers, i.e. vservers, to use user namespaces 473 to provide different user info for different servers. 474 If unsure, say N. 475 476config PID_NS 477 bool "PID Namespaces (EXPERIMENTAL)" 478 default n 479 depends on NAMESPACES && EXPERIMENTAL 480 help 481 Suport process id namespaces. This allows having multiple 482 process with the same pid as long as they are in different 483 pid namespaces. This is a building block of containers. 484 485 Unless you want to work with an experimental feature 486 say N here. 487 488config BLK_DEV_INITRD 489 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 490 depends on BROKEN || !FRV 491 help 492 The initial RAM filesystem is a ramfs which is loaded by the 493 boot loader (loadlin or lilo) and that is mounted as root 494 before the normal boot procedure. It is typically used to 495 load modules needed to mount the "real" root file system, 496 etc. See <file:Documentation/initrd.txt> for details. 497 498 If RAM disk support (BLK_DEV_RAM) is also included, this 499 also enables initial RAM disk (initrd) support and adds 500 15 Kbytes (more on some other architectures) to the kernel size. 501 502 If unsure say Y. 503 504if BLK_DEV_INITRD 505 506source "usr/Kconfig" 507 508endif 509 510config CC_OPTIMIZE_FOR_SIZE 511 bool "Optimize for size" 512 default y 513 help 514 Enabling this option will pass "-Os" instead of "-O2" to gcc 515 resulting in a smaller kernel. 516 517 If unsure, say N. 518 519config SYSCTL 520 bool 521 522menuconfig EMBEDDED 523 bool "Configure standard kernel features (for small systems)" 524 help 525 This option allows certain base kernel options and settings 526 to be disabled or tweaked. This is for specialized 527 environments which can tolerate a "non-standard" kernel. 528 Only use this if you really know what you are doing. 529 530config UID16 531 bool "Enable 16-bit UID system calls" if EMBEDDED 532 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 533 default y 534 help 535 This enables the legacy 16-bit UID syscall wrappers. 536 537config SYSCTL_SYSCALL 538 bool "Sysctl syscall support" if EMBEDDED 539 default y 540 select SYSCTL 541 ---help--- 542 sys_sysctl uses binary paths that have been found challenging 543 to properly maintain and use. The interface in /proc/sys 544 using paths with ascii names is now the primary path to this 545 information. 546 547 Almost nothing using the binary sysctl interface so if you are 548 trying to save some space it is probably safe to disable this, 549 making your kernel marginally smaller. 550 551 If unsure say Y here. 552 553config SYSCTL_SYSCALL_CHECK 554 bool "Sysctl checks" if EMBEDDED 555 depends on SYSCTL_SYSCALL 556 default y 557 ---help--- 558 sys_sysctl uses binary paths that have been found challenging 559 to properly maintain and use. This enables checks that help 560 you to keep things correct. 561 562 If unsure say Y here. 563 564config KALLSYMS 565 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 566 default y 567 help 568 Say Y here to let the kernel print out symbolic crash information and 569 symbolic stack backtraces. This increases the size of the kernel 570 somewhat, as all symbols have to be loaded into the kernel image. 571 572config KALLSYMS_ALL 573 bool "Include all symbols in kallsyms" 574 depends on DEBUG_KERNEL && KALLSYMS 575 help 576 Normally kallsyms only contains the symbols of functions, for nicer 577 OOPS messages. Some debuggers can use kallsyms for other 578 symbols too: say Y here to include all symbols, if you need them 579 and you don't care about adding 300k to the size of your kernel. 580 581 Say N. 582 583config KALLSYMS_EXTRA_PASS 584 bool "Do an extra kallsyms pass" 585 depends on KALLSYMS 586 help 587 If kallsyms is not working correctly, the build will fail with 588 inconsistent kallsyms data. If that occurs, log a bug report and 589 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 590 Always say N here unless you find a bug in kallsyms, which must be 591 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 592 you wait for kallsyms to be fixed. 593 594 595config HOTPLUG 596 bool "Support for hot-pluggable devices" if EMBEDDED 597 default y 598 help 599 This option is provided for the case where no hotplug or uevent 600 capabilities is wanted by the kernel. You should only consider 601 disabling this option for embedded systems that do not use modules, a 602 dynamic /dev tree, or dynamic device discovery. Just say Y. 603 604config PRINTK 605 default y 606 bool "Enable support for printk" if EMBEDDED 607 help 608 This option enables normal printk support. Removing it 609 eliminates most of the message strings from the kernel image 610 and makes the kernel more or less silent. As this makes it 611 very difficult to diagnose system problems, saying N here is 612 strongly discouraged. 613 614config BUG 615 bool "BUG() support" if EMBEDDED 616 default y 617 help 618 Disabling this option eliminates support for BUG and WARN, reducing 619 the size of your kernel image and potentially quietly ignoring 620 numerous fatal conditions. You should only consider disabling this 621 option for embedded systems with no facilities for reporting errors. 622 Just say Y. 623 624config ELF_CORE 625 default y 626 bool "Enable ELF core dumps" if EMBEDDED 627 help 628 Enable support for generating core dumps. Disabling saves about 4k. 629 630config COMPAT_BRK 631 bool "Disable heap randomization" 632 default y 633 help 634 Randomizing heap placement makes heap exploits harder, but it 635 also breaks ancient binaries (including anything libc5 based). 636 This option changes the bootup default to heap randomization 637 disabled, and can be overriden runtime by setting 638 /proc/sys/kernel/randomize_va_space to 2. 639 640 On non-ancient distros (post-2000 ones) N is usually a safe choice. 641 642config BASE_FULL 643 default y 644 bool "Enable full-sized data structures for core" if EMBEDDED 645 help 646 Disabling this option reduces the size of miscellaneous core 647 kernel data structures. This saves memory on small machines, 648 but may reduce performance. 649 650config FUTEX 651 bool "Enable futex support" if EMBEDDED 652 default y 653 select RT_MUTEXES 654 help 655 Disabling this option will cause the kernel to be built without 656 support for "fast userspace mutexes". The resulting kernel may not 657 run glibc-based applications correctly. 658 659config ANON_INODES 660 bool 661 662config EPOLL 663 bool "Enable eventpoll support" if EMBEDDED 664 default y 665 select ANON_INODES 666 help 667 Disabling this option will cause the kernel to be built without 668 support for epoll family of system calls. 669 670config SIGNALFD 671 bool "Enable signalfd() system call" if EMBEDDED 672 select ANON_INODES 673 default y 674 help 675 Enable the signalfd() system call that allows to receive signals 676 on a file descriptor. 677 678 If unsure, say Y. 679 680config TIMERFD 681 bool "Enable timerfd() system call" if EMBEDDED 682 select ANON_INODES 683 default y 684 help 685 Enable the timerfd() system call that allows to receive timer 686 events on a file descriptor. 687 688 If unsure, say Y. 689 690config EVENTFD 691 bool "Enable eventfd() system call" if EMBEDDED 692 select ANON_INODES 693 default y 694 help 695 Enable the eventfd() system call that allows to receive both 696 kernel notification (ie. KAIO) or userspace notifications. 697 698 If unsure, say Y. 699 700config SHMEM 701 bool "Use full shmem filesystem" if EMBEDDED 702 default y 703 depends on MMU 704 help 705 The shmem is an internal filesystem used to manage shared memory. 706 It is backed by swap and manages resource limits. It is also exported 707 to userspace as tmpfs if TMPFS is enabled. Disabling this 708 option replaces shmem and tmpfs with the much simpler ramfs code, 709 which may be appropriate on small systems without swap. 710 711config VM_EVENT_COUNTERS 712 default y 713 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 714 help 715 VM event counters are needed for event counts to be shown. 716 This option allows the disabling of the VM event counters 717 on EMBEDDED systems. /proc/vmstat will only show page counts 718 if VM event counters are disabled. 719 720config SLUB_DEBUG 721 default y 722 bool "Enable SLUB debugging support" if EMBEDDED 723 depends on SLUB 724 help 725 SLUB has extensive debug support features. Disabling these can 726 result in significant savings in code size. This also disables 727 SLUB sysfs support. /sys/slab will not exist and there will be 728 no support for cache validation etc. 729 730choice 731 prompt "Choose SLAB allocator" 732 default SLUB 733 help 734 This option allows to select a slab allocator. 735 736config SLAB 737 bool "SLAB" 738 help 739 The regular slab allocator that is established and known to work 740 well in all environments. It organizes cache hot objects in 741 per cpu and per node queues. SLAB is the default choice for 742 a slab allocator. 743 744config SLUB 745 bool "SLUB (Unqueued Allocator)" 746 help 747 SLUB is a slab allocator that minimizes cache line usage 748 instead of managing queues of cached objects (SLAB approach). 749 Per cpu caching is realized using slabs of objects instead 750 of queues of objects. SLUB can use memory efficiently 751 and has enhanced diagnostics. 752 753config SLOB 754 depends on EMBEDDED 755 bool "SLOB (Simple Allocator)" 756 help 757 SLOB replaces the stock allocator with a drastically simpler 758 allocator. SLOB is generally more space efficient but 759 does not perform as well on large systems. 760 761endchoice 762 763config PROFILING 764 bool "Profiling support (EXPERIMENTAL)" 765 help 766 Say Y here to enable the extended profiling support mechanisms used 767 by profilers such as OProfile. 768 769config MARKERS 770 bool "Activate markers" 771 help 772 Place an empty function call at each marker site. Can be 773 dynamically changed for a probe function. 774 775source "arch/Kconfig" 776 777config PROC_PAGE_MONITOR 778 default y 779 depends on PROC_FS && MMU 780 bool "Enable /proc page monitoring" if EMBEDDED 781 help 782 Various /proc files exist to monitor process memory utilization: 783 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, 784 /proc/kpagecount, and /proc/kpageflags. Disabling these 785 interfaces will reduce the size of the kernel by approximately 4kb. 786 787endmenu # General setup 788 789config SLABINFO 790 bool 791 depends on PROC_FS 792 depends on SLAB || SLUB_DEBUG 793 default y 794 795config RT_MUTEXES 796 boolean 797 select PLIST 798 799config TINY_SHMEM 800 default !SHMEM 801 bool 802 803config BASE_SMALL 804 int 805 default 0 if BASE_FULL 806 default 1 if !BASE_FULL 807 808menuconfig MODULES 809 bool "Enable loadable module support" 810 help 811 Kernel modules are small pieces of compiled code which can 812 be inserted in the running kernel, rather than being 813 permanently built into the kernel. You use the "modprobe" 814 tool to add (and sometimes remove) them. If you say Y here, 815 many parts of the kernel can be built as modules (by 816 answering M instead of Y where indicated): this is most 817 useful for infrequently used options which are not required 818 for booting. For more information, see the man pages for 819 modprobe, lsmod, modinfo, insmod and rmmod. 820 821 If you say Y here, you will need to run "make 822 modules_install" to put the modules under /lib/modules/ 823 where modprobe can find them (you may need to be root to do 824 this). 825 826 If unsure, say Y. 827 828config MODULE_UNLOAD 829 bool "Module unloading" 830 depends on MODULES 831 help 832 Without this option you will not be able to unload any 833 modules (note that some modules may not be unloadable 834 anyway), which makes your kernel slightly smaller and 835 simpler. If unsure, say Y. 836 837config MODULE_FORCE_UNLOAD 838 bool "Forced module unloading" 839 depends on MODULE_UNLOAD && EXPERIMENTAL 840 help 841 This option allows you to force a module to unload, even if the 842 kernel believes it is unsafe: the kernel will remove the module 843 without waiting for anyone to stop using it (using the -f option to 844 rmmod). This is mainly for kernel developers and desperate users. 845 If unsure, say N. 846 847config MODVERSIONS 848 bool "Module versioning support" 849 depends on MODULES 850 help 851 Usually, you have to use modules compiled with your kernel. 852 Saying Y here makes it sometimes possible to use modules 853 compiled for different kernels, by adding enough information 854 to the modules to (hopefully) spot any changes which would 855 make them incompatible with the kernel you are running. If 856 unsure, say N. 857 858config MODULE_SRCVERSION_ALL 859 bool "Source checksum for all modules" 860 depends on MODULES 861 help 862 Modules which contain a MODULE_VERSION get an extra "srcversion" 863 field inserted into their modinfo section, which contains a 864 sum of the source files which made it. This helps maintainers 865 see exactly which source was used to build a module (since 866 others sometimes change the module source without updating 867 the version). With this option, such a "srcversion" field 868 will be created for all modules. If unsure, say N. 869 870config KMOD 871 bool "Automatic kernel module loading" 872 depends on MODULES 873 help 874 Normally when you have selected some parts of the kernel to 875 be created as kernel modules, you must load them (using the 876 "modprobe" command) before you can use them. If you say Y 877 here, some parts of the kernel will be able to load modules 878 automatically: when a part of the kernel needs a module, it 879 runs modprobe with the appropriate arguments, thereby 880 loading the module if it is available. If unsure, say Y. 881 882config STOP_MACHINE 883 bool 884 default y 885 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 886 help 887 Need stop_machine() primitive. 888 889source "block/Kconfig" 890 891config PREEMPT_NOTIFIERS 892 bool 893 894config CLASSIC_RCU 895 def_bool !PREEMPT_RCU 896 help 897 This option selects the classic RCU implementation that is 898 designed for best read-side performance on non-realtime 899 systems. Classic RCU is the default. Note that the 900 PREEMPT_RCU symbol is used to select/deselect this option. 901