1config DEFCONFIG_LIST 2 string 3 depends on !UML 4 option defconfig_list 5 default "/lib/modules/$UNAME_RELEASE/.config" 6 default "/etc/kernel-config" 7 default "/boot/config-$UNAME_RELEASE" 8 default "arch/$ARCH/defconfig" 9 10menu "General setup" 11 12config EXPERIMENTAL 13 bool "Prompt for development and/or incomplete code/drivers" 14 ---help--- 15 Some of the various things that Linux supports (such as network 16 drivers, file systems, network protocols, etc.) can be in a state 17 of development where the functionality, stability, or the level of 18 testing is not yet high enough for general use. This is usually 19 known as the "alpha-test" phase among developers. If a feature is 20 currently in alpha-test, then the developers usually discourage 21 uninformed widespread use of this feature by the general public to 22 avoid "Why doesn't this work?" type mail messages. However, active 23 testing and use of these systems is welcomed. Just be aware that it 24 may not meet the normal level of reliability or it may fail to work 25 in some special cases. Detailed bug reports from people familiar 26 with the kernel internals are usually welcomed by the developers 27 (before submitting bug reports, please read the documents 28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 29 <file:Documentation/BUG-HUNTING>, and 30 <file:Documentation/oops-tracing.txt> in the kernel source). 31 32 This option will also make obsoleted drivers available. These are 33 drivers that have been replaced by something else, and/or are 34 scheduled to be removed in a future kernel release. 35 36 Unless you intend to help test and develop a feature or driver that 37 falls into this category, or you have a situation that requires 38 using these features, you should probably say N here, which will 39 cause the configurator to present you with fewer choices. If 40 you say Y here, you will be offered the choice of using features or 41 drivers that are currently considered to be in the alpha-test phase. 42 43config BROKEN 44 bool 45 46config BROKEN_ON_SMP 47 bool 48 depends on BROKEN || !SMP 49 default y 50 51config LOCK_KERNEL 52 bool 53 depends on SMP || PREEMPT 54 default y 55 56config INIT_ENV_ARG_LIMIT 57 int 58 default 32 if !UML 59 default 128 if UML 60 help 61 Maximum of each of the number of arguments and environment 62 variables passed to init from the kernel command line. 63 64 65config LOCALVERSION 66 string "Local version - append to kernel release" 67 help 68 Append an extra string to the end of your kernel version. 69 This will show up when you type uname, for example. 70 The string you set here will be appended after the contents of 71 any files with a filename matching localversion* in your 72 object and source tree, in that order. Your total string can 73 be a maximum of 64 characters. 74 75config LOCALVERSION_AUTO 76 bool "Automatically append version information to the version string" 77 default y 78 help 79 This will try to automatically determine if the current tree is a 80 release tree by looking for git tags that belong to the current 81 top of tree revision. 82 83 A string of the format -gxxxxxxxx will be added to the localversion 84 if a git-based tree is found. The string generated by this will be 85 appended after any matching localversion* files, and after the value 86 set in CONFIG_LOCALVERSION. 87 88 (The actual string used here is the first eight characters produced 89 by running the command: 90 91 $ git rev-parse --verify HEAD 92 93 which is done within the script "scripts/setlocalversion".) 94 95config SWAP 96 bool "Support for paging of anonymous memory (swap)" 97 depends on MMU && BLOCK 98 default y 99 help 100 This option allows you to choose whether you want to have support 101 for so called swap devices or swap files in your kernel that are 102 used to provide more virtual memory than the actual RAM present 103 in your computer. If unsure say Y. 104 105config SYSVIPC 106 bool "System V IPC" 107 ---help--- 108 Inter Process Communication is a suite of library functions and 109 system calls which let processes (running programs) synchronize and 110 exchange information. It is generally considered to be a good thing, 111 and some programs won't run unless you say Y here. In particular, if 112 you want to run the DOS emulator dosemu under Linux (read the 113 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 114 you'll need to say Y here. 115 116 You can find documentation about IPC with "info ipc" and also in 117 section 6.4 of the Linux Programmer's Guide, available from 118 <http://www.tldp.org/guides.html>. 119 120config SYSVIPC_SYSCTL 121 bool 122 depends on SYSVIPC 123 depends on SYSCTL 124 default y 125 126config POSIX_MQUEUE 127 bool "POSIX Message Queues" 128 depends on NET && EXPERIMENTAL 129 ---help--- 130 POSIX variant of message queues is a part of IPC. In POSIX message 131 queues every message has a priority which decides about succession 132 of receiving it by a process. If you want to compile and run 133 programs written e.g. for Solaris with use of its POSIX message 134 queues (functions mq_*) say Y here. 135 136 POSIX message queues are visible as a filesystem called 'mqueue' 137 and can be mounted somewhere if you want to do filesystem 138 operations on message queues. 139 140 If unsure, say Y. 141 142config BSD_PROCESS_ACCT 143 bool "BSD Process Accounting" 144 help 145 If you say Y here, a user level program will be able to instruct the 146 kernel (via a special system call) to write process accounting 147 information to a file: whenever a process exits, information about 148 that process will be appended to the file by the kernel. The 149 information includes things such as creation time, owning user, 150 command name, memory usage, controlling terminal etc. (the complete 151 list is in the struct acct in <file:include/linux/acct.h>). It is 152 up to the user level program to do useful things with this 153 information. This is generally a good idea, so say Y. 154 155config BSD_PROCESS_ACCT_V3 156 bool "BSD Process Accounting version 3 file format" 157 depends on BSD_PROCESS_ACCT 158 default n 159 help 160 If you say Y here, the process accounting information is written 161 in a new file format that also logs the process IDs of each 162 process and it's parent. Note that this file format is incompatible 163 with previous v0/v1/v2 file formats, so you will need updated tools 164 for processing it. A preliminary version of these tools is available 165 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 166 167config TASKSTATS 168 bool "Export task/process statistics through netlink (EXPERIMENTAL)" 169 depends on NET 170 default n 171 help 172 Export selected statistics for tasks/processes through the 173 generic netlink interface. Unlike BSD process accounting, the 174 statistics are available during the lifetime of tasks/processes as 175 responses to commands. Like BSD accounting, they are sent to user 176 space on task exit. 177 178 Say N if unsure. 179 180config TASK_DELAY_ACCT 181 bool "Enable per-task delay accounting (EXPERIMENTAL)" 182 depends on TASKSTATS 183 help 184 Collect information on time spent by a task waiting for system 185 resources like cpu, synchronous block I/O completion and swapping 186 in pages. Such statistics can help in setting a task's priorities 187 relative to other tasks for cpu, io, rss limits etc. 188 189 Say N if unsure. 190 191config TASK_XACCT 192 bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 193 depends on TASKSTATS 194 help 195 Collect extended task accounting data and send the data 196 to userland for processing over the taskstats interface. 197 198 Say N if unsure. 199 200config TASK_IO_ACCOUNTING 201 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 202 depends on TASK_XACCT 203 help 204 Collect information on the number of bytes of storage I/O which this 205 task has caused. 206 207 Say N if unsure. 208 209config USER_NS 210 bool "User Namespaces (EXPERIMENTAL)" 211 default n 212 depends on EXPERIMENTAL 213 help 214 Support user namespaces. This allows containers, i.e. 215 vservers, to use user namespaces to provide different 216 user info for different servers. If unsure, say N. 217 218config AUDIT 219 bool "Auditing support" 220 depends on NET 221 help 222 Enable auditing infrastructure that can be used with another 223 kernel subsystem, such as SELinux (which requires this for 224 logging of avc messages output). Does not do system-call 225 auditing without CONFIG_AUDITSYSCALL. 226 227config AUDITSYSCALL 228 bool "Enable system-call auditing support" 229 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64) 230 default y if SECURITY_SELINUX 231 help 232 Enable low-overhead system-call auditing infrastructure that 233 can be used independently or with another kernel subsystem, 234 such as SELinux. To use audit's filesystem watch feature, please 235 ensure that INOTIFY is configured. 236 237config IKCONFIG 238 tristate "Kernel .config support" 239 ---help--- 240 This option enables the complete Linux kernel ".config" file 241 contents to be saved in the kernel. It provides documentation 242 of which kernel options are used in a running kernel or in an 243 on-disk kernel. This information can be extracted from the kernel 244 image file with the script scripts/extract-ikconfig and used as 245 input to rebuild the current kernel or to build another kernel. 246 It can also be extracted from a running kernel by reading 247 /proc/config.gz if enabled (below). 248 249config IKCONFIG_PROC 250 bool "Enable access to .config through /proc/config.gz" 251 depends on IKCONFIG && PROC_FS 252 ---help--- 253 This option enables access to the kernel configuration file 254 through /proc/config.gz. 255 256config LOG_BUF_SHIFT 257 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 258 range 12 21 259 default 17 if S390 || LOCKDEP 260 default 16 if X86_NUMAQ || IA64 261 default 15 if SMP 262 default 14 263 help 264 Select kernel log buffer size as a power of 2. 265 Defaults and Examples: 266 17 => 128 KB for S/390 267 16 => 64 KB for x86 NUMAQ or IA-64 268 15 => 32 KB for SMP 269 14 => 16 KB for uniprocessor 270 13 => 8 KB 271 12 => 4 KB 272 273config 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 help 285 This option enables a simple cgroup subsystem that 286 exports useful debugging information about the cgroups 287 framework 288 289 Say N if unsure 290 291config CGROUP_NS 292 bool "Namespace cgroup subsystem" 293 depends on CGROUPS 294 help 295 Provides a simple namespace cgroup subsystem to 296 provide hierarchical naming of sets of namespaces, 297 for instance virtual servers and checkpoint/restart 298 jobs. 299 300config CGROUP_CPUACCT 301 bool "Simple CPU accounting cgroup subsystem" 302 depends on CGROUPS 303 help 304 Provides a simple Resource Controller for monitoring the 305 total CPU consumed by the tasks in a cgroup 306 307config CPUSETS 308 bool "Cpuset support" 309 depends on SMP && CGROUPS 310 help 311 This option will let you create and manage CPUSETs which 312 allow dynamically partitioning a system into sets of CPUs and 313 Memory Nodes and assigning tasks to run only within those sets. 314 This is primarily useful on large SMP or NUMA systems. 315 316 Say N if unsure. 317 318config FAIR_GROUP_SCHED 319 bool "Fair group CPU scheduler" 320 default y 321 depends on EXPERIMENTAL 322 help 323 This feature lets CPU scheduler recognize task groups and control CPU 324 bandwidth allocation to such task groups. 325 326choice 327 depends on FAIR_GROUP_SCHED 328 prompt "Basis for grouping tasks" 329 default FAIR_USER_SCHED 330 331config FAIR_USER_SCHED 332 bool "user id" 333 help 334 This option will choose userid as the basis for grouping 335 tasks, thus providing equal CPU bandwidth to each user. 336 337config FAIR_CGROUP_SCHED 338 bool "Control groups" 339 depends on CGROUPS 340 help 341 This option allows you to create arbitrary task groups 342 using the "cgroup" pseudo filesystem and control 343 the cpu bandwidth allocated to each such task group. 344 Refer to Documentation/cgroups.txt for more information 345 on "cgroup" pseudo filesystem. 346 347endchoice 348 349config SYSFS_DEPRECATED 350 bool "Create deprecated sysfs files" 351 default y 352 help 353 This option creates deprecated symlinks such as the 354 "device"-link, the <subsystem>:<name>-link, and the 355 "bus"-link. It may also add deprecated key in the 356 uevent environment. 357 None of these features or values should be used today, as 358 they export driver core implementation details to userspace 359 or export properties which can't be kept stable across kernel 360 releases. 361 362 If enabled, this option will also move any device structures 363 that belong to a class, back into the /sys/class hierarchy, in 364 order to support older versions of udev. 365 366 If you are using a distro that was released in 2006 or later, 367 it should be safe to say N here. 368 369config PROC_PID_CPUSET 370 bool "Include legacy /proc/<pid>/cpuset file" 371 depends on CPUSETS 372 default y 373 374config RELAY 375 bool "Kernel->user space relay support (formerly relayfs)" 376 help 377 This option enables support for relay interface support in 378 certain file systems (such as debugfs). 379 It is designed to provide an efficient mechanism for tools and 380 facilities to relay large amounts of data from kernel space to 381 user space. 382 383 If unsure, say N. 384 385config BLK_DEV_INITRD 386 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 387 depends on BROKEN || !FRV 388 help 389 The initial RAM filesystem is a ramfs which is loaded by the 390 boot loader (loadlin or lilo) and that is mounted as root 391 before the normal boot procedure. It is typically used to 392 load modules needed to mount the "real" root file system, 393 etc. See <file:Documentation/initrd.txt> for details. 394 395 If RAM disk support (BLK_DEV_RAM) is also included, this 396 also enables initial RAM disk (initrd) support and adds 397 15 Kbytes (more on some other architectures) to the kernel size. 398 399 If unsure say Y. 400 401if BLK_DEV_INITRD 402 403source "usr/Kconfig" 404 405endif 406 407config CC_OPTIMIZE_FOR_SIZE 408 bool "Optimize for size (Look out for broken compilers!)" 409 default y 410 depends on ARM || H8300 || SUPERH || EXPERIMENTAL 411 help 412 Enabling this option will pass "-Os" instead of "-O2" to gcc 413 resulting in a smaller kernel. 414 415 WARNING: some versions of gcc may generate incorrect code with this 416 option. If problems are observed, a gcc upgrade may be needed. 417 418 If unsure, say N. 419 420config SYSCTL 421 bool 422 423menuconfig EMBEDDED 424 bool "Configure standard kernel features (for small systems)" 425 help 426 This option allows certain base kernel options and settings 427 to be disabled or tweaked. This is for specialized 428 environments which can tolerate a "non-standard" kernel. 429 Only use this if you really know what you are doing. 430 431config UID16 432 bool "Enable 16-bit UID system calls" if EMBEDDED 433 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 434 default y 435 help 436 This enables the legacy 16-bit UID syscall wrappers. 437 438config SYSCTL_SYSCALL 439 bool "Sysctl syscall support" if EMBEDDED 440 default y 441 select SYSCTL 442 ---help--- 443 sys_sysctl uses binary paths that have been found challenging 444 to properly maintain and use. The interface in /proc/sys 445 using paths with ascii names is now the primary path to this 446 information. 447 448 Almost nothing using the binary sysctl interface so if you are 449 trying to save some space it is probably safe to disable this, 450 making your kernel marginally smaller. 451 452 If unsure say Y here. 453 454config KALLSYMS 455 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 456 default y 457 help 458 Say Y here to let the kernel print out symbolic crash information and 459 symbolic stack backtraces. This increases the size of the kernel 460 somewhat, as all symbols have to be loaded into the kernel image. 461 462config KALLSYMS_ALL 463 bool "Include all symbols in kallsyms" 464 depends on DEBUG_KERNEL && KALLSYMS 465 help 466 Normally kallsyms only contains the symbols of functions, for nicer 467 OOPS messages. Some debuggers can use kallsyms for other 468 symbols too: say Y here to include all symbols, if you need them 469 and you don't care about adding 300k to the size of your kernel. 470 471 Say N. 472 473config KALLSYMS_EXTRA_PASS 474 bool "Do an extra kallsyms pass" 475 depends on KALLSYMS 476 help 477 If kallsyms is not working correctly, the build will fail with 478 inconsistent kallsyms data. If that occurs, log a bug report and 479 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 480 Always say N here unless you find a bug in kallsyms, which must be 481 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 482 you wait for kallsyms to be fixed. 483 484 485config HOTPLUG 486 bool "Support for hot-pluggable devices" if EMBEDDED 487 default y 488 help 489 This option is provided for the case where no hotplug or uevent 490 capabilities is wanted by the kernel. You should only consider 491 disabling this option for embedded systems that do not use modules, a 492 dynamic /dev tree, or dynamic device discovery. Just say Y. 493 494config PRINTK 495 default y 496 bool "Enable support for printk" if EMBEDDED 497 help 498 This option enables normal printk support. Removing it 499 eliminates most of the message strings from the kernel image 500 and makes the kernel more or less silent. As this makes it 501 very difficult to diagnose system problems, saying N here is 502 strongly discouraged. 503 504config BUG 505 bool "BUG() support" if EMBEDDED 506 default y 507 help 508 Disabling this option eliminates support for BUG and WARN, reducing 509 the size of your kernel image and potentially quietly ignoring 510 numerous fatal conditions. You should only consider disabling this 511 option for embedded systems with no facilities for reporting errors. 512 Just say Y. 513 514config ELF_CORE 515 default y 516 bool "Enable ELF core dumps" if EMBEDDED 517 help 518 Enable support for generating core dumps. Disabling saves about 4k. 519 520config BASE_FULL 521 default y 522 bool "Enable full-sized data structures for core" if EMBEDDED 523 help 524 Disabling this option reduces the size of miscellaneous core 525 kernel data structures. This saves memory on small machines, 526 but may reduce performance. 527 528config FUTEX 529 bool "Enable futex support" if EMBEDDED 530 default y 531 select RT_MUTEXES 532 help 533 Disabling this option will cause the kernel to be built without 534 support for "fast userspace mutexes". The resulting kernel may not 535 run glibc-based applications correctly. 536 537config ANON_INODES 538 bool 539 540config EPOLL 541 bool "Enable eventpoll support" if EMBEDDED 542 default y 543 select ANON_INODES 544 help 545 Disabling this option will cause the kernel to be built without 546 support for epoll family of system calls. 547 548config SIGNALFD 549 bool "Enable signalfd() system call" if EMBEDDED 550 select ANON_INODES 551 default y 552 help 553 Enable the signalfd() system call that allows to receive signals 554 on a file descriptor. 555 556 If unsure, say Y. 557 558config TIMERFD 559 bool "Enable timerfd() system call" if EMBEDDED 560 select ANON_INODES 561 depends on BROKEN 562 default y 563 help 564 Enable the timerfd() system call that allows to receive timer 565 events on a file descriptor. 566 567 If unsure, say Y. 568 569config EVENTFD 570 bool "Enable eventfd() system call" if EMBEDDED 571 select ANON_INODES 572 default y 573 help 574 Enable the eventfd() system call that allows to receive both 575 kernel notification (ie. KAIO) or userspace notifications. 576 577 If unsure, say Y. 578 579config SHMEM 580 bool "Use full shmem filesystem" if EMBEDDED 581 default y 582 depends on MMU 583 help 584 The shmem is an internal filesystem used to manage shared memory. 585 It is backed by swap and manages resource limits. It is also exported 586 to userspace as tmpfs if TMPFS is enabled. Disabling this 587 option replaces shmem and tmpfs with the much simpler ramfs code, 588 which may be appropriate on small systems without swap. 589 590config VM_EVENT_COUNTERS 591 default y 592 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 593 help 594 VM event counters are needed for event counts to be shown. 595 This option allows the disabling of the VM event counters 596 on EMBEDDED systems. /proc/vmstat will only show page counts 597 if VM event counters are disabled. 598 599config SLUB_DEBUG 600 default y 601 bool "Enable SLUB debugging support" if EMBEDDED 602 depends on SLUB 603 help 604 SLUB has extensive debug support features. Disabling these can 605 result in significant savings in code size. This also disables 606 SLUB sysfs support. /sys/slab will not exist and there will be 607 no support for cache validation etc. 608 609choice 610 prompt "Choose SLAB allocator" 611 default SLUB 612 help 613 This option allows to select a slab allocator. 614 615config SLAB 616 bool "SLAB" 617 help 618 The regular slab allocator that is established and known to work 619 well in all environments. It organizes cache hot objects in 620 per cpu and per node queues. SLAB is the default choice for 621 a slab allocator. 622 623config SLUB 624 bool "SLUB (Unqueued Allocator)" 625 help 626 SLUB is a slab allocator that minimizes cache line usage 627 instead of managing queues of cached objects (SLAB approach). 628 Per cpu caching is realized using slabs of objects instead 629 of queues of objects. SLUB can use memory efficiently 630 and has enhanced diagnostics. 631 632config SLOB 633 depends on EMBEDDED 634 bool "SLOB (Simple Allocator)" 635 help 636 SLOB replaces the SLAB allocator with a drastically simpler 637 allocator. SLOB is more space efficient than SLAB but does not 638 scale well (single lock for all operations) and is also highly 639 susceptible to fragmentation. SLUB can accomplish a higher object 640 density. It is usually better to use SLUB instead of SLOB. 641 642endchoice 643 644endmenu # General setup 645 646config RT_MUTEXES 647 boolean 648 select PLIST 649 650config TINY_SHMEM 651 default !SHMEM 652 bool 653 654config BASE_SMALL 655 int 656 default 0 if BASE_FULL 657 default 1 if !BASE_FULL 658 659menuconfig MODULES 660 bool "Enable loadable module support" 661 help 662 Kernel modules are small pieces of compiled code which can 663 be inserted in the running kernel, rather than being 664 permanently built into the kernel. You use the "modprobe" 665 tool to add (and sometimes remove) them. If you say Y here, 666 many parts of the kernel can be built as modules (by 667 answering M instead of Y where indicated): this is most 668 useful for infrequently used options which are not required 669 for booting. For more information, see the man pages for 670 modprobe, lsmod, modinfo, insmod and rmmod. 671 672 If you say Y here, you will need to run "make 673 modules_install" to put the modules under /lib/modules/ 674 where modprobe can find them (you may need to be root to do 675 this). 676 677 If unsure, say Y. 678 679config MODULE_UNLOAD 680 bool "Module unloading" 681 depends on MODULES 682 help 683 Without this option you will not be able to unload any 684 modules (note that some modules may not be unloadable 685 anyway), which makes your kernel slightly smaller and 686 simpler. If unsure, say Y. 687 688config MODULE_FORCE_UNLOAD 689 bool "Forced module unloading" 690 depends on MODULE_UNLOAD && EXPERIMENTAL 691 help 692 This option allows you to force a module to unload, even if the 693 kernel believes it is unsafe: the kernel will remove the module 694 without waiting for anyone to stop using it (using the -f option to 695 rmmod). This is mainly for kernel developers and desperate users. 696 If unsure, say N. 697 698config MODVERSIONS 699 bool "Module versioning support" 700 depends on MODULES 701 help 702 Usually, you have to use modules compiled with your kernel. 703 Saying Y here makes it sometimes possible to use modules 704 compiled for different kernels, by adding enough information 705 to the modules to (hopefully) spot any changes which would 706 make them incompatible with the kernel you are running. If 707 unsure, say N. 708 709config MODULE_SRCVERSION_ALL 710 bool "Source checksum for all modules" 711 depends on MODULES 712 help 713 Modules which contain a MODULE_VERSION get an extra "srcversion" 714 field inserted into their modinfo section, which contains a 715 sum of the source files which made it. This helps maintainers 716 see exactly which source was used to build a module (since 717 others sometimes change the module source without updating 718 the version). With this option, such a "srcversion" field 719 will be created for all modules. If unsure, say N. 720 721config KMOD 722 bool "Automatic kernel module loading" 723 depends on MODULES 724 help 725 Normally when you have selected some parts of the kernel to 726 be created as kernel modules, you must load them (using the 727 "modprobe" command) before you can use them. If you say Y 728 here, some parts of the kernel will be able to load modules 729 automatically: when a part of the kernel needs a module, it 730 runs modprobe with the appropriate arguments, thereby 731 loading the module if it is available. If unsure, say Y. 732 733config STOP_MACHINE 734 bool 735 default y 736 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 737 help 738 Need stop_machine() primitive. 739 740source "block/Kconfig" 741 742config PREEMPT_NOTIFIERS 743 bool 744