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 These are 42 drivers that have been replaced by something else, and/or are 43 scheduled to be removed in a future kernel release. 44 45 Unless you intend to help test and develop a feature or driver that 46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.gnu.org/software/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 241menu "RCU Subsystem" 242 243choice 244 prompt "RCU Implementation" 245 default CLASSIC_RCU 246 247config CLASSIC_RCU 248 bool "Classic RCU" 249 help 250 This option selects the classic RCU implementation that is 251 designed for best read-side performance on non-realtime 252 systems. 253 254 Select this option if you are unsure. 255 256config TREE_RCU 257 bool "Tree-based hierarchical RCU" 258 help 259 This option selects the RCU implementation that is 260 designed for very large SMP system with hundreds or 261 thousands of CPUs. 262 263config PREEMPT_RCU 264 bool "Preemptible RCU" 265 depends on PREEMPT 266 help 267 This option reduces the latency of the kernel by making certain 268 RCU sections preemptible. Normally RCU code is non-preemptible, if 269 this option is selected then read-only RCU sections become 270 preemptible. This helps latency, but may expose bugs due to 271 now-naive assumptions about each RCU read-side critical section 272 remaining on a given CPU through its execution. 273 274endchoice 275 276config RCU_TRACE 277 bool "Enable tracing for RCU" 278 depends on TREE_RCU || PREEMPT_RCU 279 help 280 This option provides tracing in RCU which presents stats 281 in debugfs for debugging RCU implementation. 282 283 Say Y here if you want to enable RCU tracing 284 Say N if you are unsure. 285 286config RCU_FANOUT 287 int "Tree-based hierarchical RCU fanout value" 288 range 2 64 if 64BIT 289 range 2 32 if !64BIT 290 depends on TREE_RCU 291 default 64 if 64BIT 292 default 32 if !64BIT 293 help 294 This option controls the fanout of hierarchical implementations 295 of RCU, allowing RCU to work efficiently on machines with 296 large numbers of CPUs. This value must be at least the cube 297 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit 298 systems and up to 262,144 for 64-bit systems. 299 300 Select a specific number if testing RCU itself. 301 Take the default if unsure. 302 303config RCU_FANOUT_EXACT 304 bool "Disable tree-based hierarchical RCU auto-balancing" 305 depends on TREE_RCU 306 default n 307 help 308 This option forces use of the exact RCU_FANOUT value specified, 309 regardless of imbalances in the hierarchy. This is useful for 310 testing RCU itself, and might one day be useful on systems with 311 strong NUMA behavior. 312 313 Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 314 315 Say N if unsure. 316 317config TREE_RCU_TRACE 318 def_bool RCU_TRACE && TREE_RCU 319 select DEBUG_FS 320 help 321 This option provides tracing for the TREE_RCU implementation, 322 permitting Makefile to trivially select kernel/rcutree_trace.c. 323 324config PREEMPT_RCU_TRACE 325 def_bool RCU_TRACE && PREEMPT_RCU 326 select DEBUG_FS 327 help 328 This option provides tracing for the PREEMPT_RCU implementation, 329 permitting Makefile to trivially select kernel/rcupreempt_trace.c. 330 331endmenu # "RCU Subsystem" 332 333config IKCONFIG 334 tristate "Kernel .config support" 335 ---help--- 336 This option enables the complete Linux kernel ".config" file 337 contents to be saved in the kernel. It provides documentation 338 of which kernel options are used in a running kernel or in an 339 on-disk kernel. This information can be extracted from the kernel 340 image file with the script scripts/extract-ikconfig and used as 341 input to rebuild the current kernel or to build another kernel. 342 It can also be extracted from a running kernel by reading 343 /proc/config.gz if enabled (below). 344 345config IKCONFIG_PROC 346 bool "Enable access to .config through /proc/config.gz" 347 depends on IKCONFIG && PROC_FS 348 ---help--- 349 This option enables access to the kernel configuration file 350 through /proc/config.gz. 351 352config LOG_BUF_SHIFT 353 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 354 range 12 21 355 default 17 356 help 357 Select kernel log buffer size as a power of 2. 358 Examples: 359 17 => 128 KB 360 16 => 64 KB 361 15 => 32 KB 362 14 => 16 KB 363 13 => 8 KB 364 12 => 4 KB 365 366# 367# Architectures with an unreliable sched_clock() should select this: 368# 369config HAVE_UNSTABLE_SCHED_CLOCK 370 bool 371 372config GROUP_SCHED 373 bool "Group CPU scheduler" 374 depends on EXPERIMENTAL 375 default n 376 help 377 This feature lets CPU scheduler recognize task groups and control CPU 378 bandwidth allocation to such task groups. 379 In order to create a group from arbitrary set of processes, use 380 CONFIG_CGROUPS. (See Control Group support.) 381 382config FAIR_GROUP_SCHED 383 bool "Group scheduling for SCHED_OTHER" 384 depends on GROUP_SCHED 385 default GROUP_SCHED 386 387config RT_GROUP_SCHED 388 bool "Group scheduling for SCHED_RR/FIFO" 389 depends on EXPERIMENTAL 390 depends on GROUP_SCHED 391 default n 392 help 393 This feature lets you explicitly allocate real CPU bandwidth 394 to users or control groups (depending on the "Basis for grouping tasks" 395 setting below. If enabled, it will also make it impossible to 396 schedule realtime tasks for non-root users until you allocate 397 realtime bandwidth for them. 398 See Documentation/scheduler/sched-rt-group.txt for more information. 399 400choice 401 depends on GROUP_SCHED 402 prompt "Basis for grouping tasks" 403 default USER_SCHED 404 405config USER_SCHED 406 bool "user id" 407 help 408 This option will choose userid as the basis for grouping 409 tasks, thus providing equal CPU bandwidth to each user. 410 411config CGROUP_SCHED 412 bool "Control groups" 413 depends on CGROUPS 414 help 415 This option allows you to create arbitrary task groups 416 using the "cgroup" pseudo filesystem and control 417 the cpu bandwidth allocated to each such task group. 418 Refer to Documentation/cgroups/cgroups.txt for more 419 information on "cgroup" pseudo filesystem. 420 421endchoice 422 423menuconfig CGROUPS 424 boolean "Control Group support" 425 help 426 This option adds support for grouping sets of processes together, for 427 use with process control subsystems such as Cpusets, CFS, memory 428 controls or device isolation. 429 See 430 - Documentation/scheduler/sched-design-CFS.txt (CFS) 431 - Documentation/cgroups/ (features for grouping, isolation 432 and resource control) 433 434 Say N if unsure. 435 436if CGROUPS 437 438config CGROUP_DEBUG 439 bool "Example debug cgroup subsystem" 440 depends on CGROUPS 441 default n 442 help 443 This option enables a simple cgroup subsystem that 444 exports useful debugging information about the cgroups 445 framework. 446 447 Say N if unsure. 448 449config CGROUP_NS 450 bool "Namespace cgroup subsystem" 451 depends on CGROUPS 452 help 453 Provides a simple namespace cgroup subsystem to 454 provide hierarchical naming of sets of namespaces, 455 for instance virtual servers and checkpoint/restart 456 jobs. 457 458config CGROUP_FREEZER 459 bool "Freezer cgroup subsystem" 460 depends on CGROUPS 461 help 462 Provides a way to freeze and unfreeze all tasks in a 463 cgroup. 464 465config CGROUP_DEVICE 466 bool "Device controller for cgroups" 467 depends on CGROUPS && EXPERIMENTAL 468 help 469 Provides a cgroup implementing whitelists for devices which 470 a process in the cgroup can mknod or open. 471 472config CPUSETS 473 bool "Cpuset support" 474 depends on SMP && CGROUPS 475 help 476 This option will let you create and manage CPUSETs which 477 allow dynamically partitioning a system into sets of CPUs and 478 Memory Nodes and assigning tasks to run only within those sets. 479 This is primarily useful on large SMP or NUMA systems. 480 481 Say N if unsure. 482 483config PROC_PID_CPUSET 484 bool "Include legacy /proc/<pid>/cpuset file" 485 depends on CPUSETS 486 default y 487 488config CGROUP_CPUACCT 489 bool "Simple CPU accounting cgroup subsystem" 490 depends on CGROUPS 491 help 492 Provides a simple Resource Controller for monitoring the 493 total CPU consumed by the tasks in a cgroup. 494 495config RESOURCE_COUNTERS 496 bool "Resource counters" 497 help 498 This option enables controller independent resource accounting 499 infrastructure that works with cgroups. 500 depends on CGROUPS 501 502config CGROUP_MEM_RES_CTLR 503 bool "Memory Resource Controller for Control Groups" 504 depends on CGROUPS && RESOURCE_COUNTERS 505 select MM_OWNER 506 help 507 Provides a memory resource controller that manages both anonymous 508 memory and page cache. (See Documentation/controllers/memory.txt) 509 510 Note that setting this option increases fixed memory overhead 511 associated with each page of memory in the system. By this, 512 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 513 usage tracking struct at boot. Total amount of this is printed out 514 at boot. 515 516 Only enable when you're ok with these trade offs and really 517 sure you need the memory resource controller. Even when you enable 518 this, you can set "cgroup_disable=memory" at your boot option to 519 disable memory resource controller and you can avoid overheads. 520 (and lose benefits of memory resource controller) 521 522 This config option also selects MM_OWNER config option, which 523 could in turn add some fork/exit overhead. 524 525config CGROUP_MEM_RES_CTLR_SWAP 526 bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)" 527 depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL 528 help 529 Add swap management feature to memory resource controller. When you 530 enable this, you can limit mem+swap usage per cgroup. In other words, 531 when you disable this, memory resource controller has no cares to 532 usage of swap...a process can exhaust all of the swap. This extension 533 is useful when you want to avoid exhaustion swap but this itself 534 adds more overheads and consumes memory for remembering information. 535 Especially if you use 32bit system or small memory system, please 536 be careful about enabling this. When memory resource controller 537 is disabled by boot option, this will be automatically disabled and 538 there will be no overhead from this. Even when you set this config=y, 539 if boot option "noswapaccount" is set, swap will not be accounted. 540 541endif # CGROUPS 542 543config MM_OWNER 544 bool 545 546config SYSFS_DEPRECATED 547 bool 548 549config SYSFS_DEPRECATED_V2 550 bool "Create deprecated sysfs layout for older userspace tools" 551 depends on SYSFS 552 default y 553 select SYSFS_DEPRECATED 554 help 555 This option switches the layout of sysfs to the deprecated 556 version. 557 558 The current sysfs layout features a unified device tree at 559 /sys/devices/, which is able to express a hierarchy between 560 class devices. If the deprecated option is set to Y, the 561 unified device tree is split into a bus device tree at 562 /sys/devices/ and several individual class device trees at 563 /sys/class/. The class and bus devices will be connected by 564 "<subsystem>:<name>" and the "device" links. The "block" 565 class devices, will not show up in /sys/class/block/. Some 566 subsystems will suppress the creation of some devices which 567 depend on the unified device tree. 568 569 This option is not a pure compatibility option that can 570 be safely enabled on newer distributions. It will change the 571 layout of sysfs to the non-extensible deprecated version, 572 and disable some features, which can not be exported without 573 confusing older userspace tools. Since 2007/2008 all major 574 distributions do not enable this option, and ship no tools which 575 depend on the deprecated layout or this option. 576 577 If you are using a new kernel on an older distribution, or use 578 older userspace tools, you might need to say Y here. Do not say Y, 579 if the original kernel, that came with your distribution, has 580 this option set to N. 581 582config RELAY 583 bool "Kernel->user space relay support (formerly relayfs)" 584 help 585 This option enables support for relay interface support in 586 certain file systems (such as debugfs). 587 It is designed to provide an efficient mechanism for tools and 588 facilities to relay large amounts of data from kernel space to 589 user space. 590 591 If unsure, say N. 592 593config NAMESPACES 594 bool "Namespaces support" if EMBEDDED 595 default !EMBEDDED 596 help 597 Provides the way to make tasks work with different objects using 598 the same id. For example same IPC id may refer to different objects 599 or same user id or pid may refer to different tasks when used in 600 different namespaces. 601 602config UTS_NS 603 bool "UTS namespace" 604 depends on NAMESPACES 605 help 606 In this namespace tasks see different info provided with the 607 uname() system call 608 609config IPC_NS 610 bool "IPC namespace" 611 depends on NAMESPACES && SYSVIPC 612 help 613 In this namespace tasks work with IPC ids which correspond to 614 different IPC objects in different namespaces 615 616config USER_NS 617 bool "User namespace (EXPERIMENTAL)" 618 depends on NAMESPACES && EXPERIMENTAL 619 help 620 This allows containers, i.e. vservers, to use user namespaces 621 to provide different user info for different servers. 622 If unsure, say N. 623 624config PID_NS 625 bool "PID Namespaces (EXPERIMENTAL)" 626 default n 627 depends on NAMESPACES && EXPERIMENTAL 628 help 629 Support process id namespaces. This allows having multiple 630 process with the same pid as long as they are in different 631 pid namespaces. This is a building block of containers. 632 633 Unless you want to work with an experimental feature 634 say N here. 635 636config NET_NS 637 bool "Network namespace" 638 default n 639 depends on NAMESPACES && EXPERIMENTAL && NET 640 help 641 Allow user space to create what appear to be multiple instances 642 of the network stack. 643 644config BLK_DEV_INITRD 645 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 646 depends on BROKEN || !FRV 647 help 648 The initial RAM filesystem is a ramfs which is loaded by the 649 boot loader (loadlin or lilo) and that is mounted as root 650 before the normal boot procedure. It is typically used to 651 load modules needed to mount the "real" root file system, 652 etc. See <file:Documentation/initrd.txt> for details. 653 654 If RAM disk support (BLK_DEV_RAM) is also included, this 655 also enables initial RAM disk (initrd) support and adds 656 15 Kbytes (more on some other architectures) to the kernel size. 657 658 If unsure say Y. 659 660if BLK_DEV_INITRD 661 662source "usr/Kconfig" 663 664endif 665 666config CC_OPTIMIZE_FOR_SIZE 667 bool "Optimize for size" 668 default y 669 help 670 Enabling this option will pass "-Os" instead of "-O2" to gcc 671 resulting in a smaller kernel. 672 673 If unsure, say Y. 674 675config SYSCTL 676 bool 677 678menuconfig EMBEDDED 679 bool "Configure standard kernel features (for small systems)" 680 help 681 This option allows certain base kernel options and settings 682 to be disabled or tweaked. This is for specialized 683 environments which can tolerate a "non-standard" kernel. 684 Only use this if you really know what you are doing. 685 686config UID16 687 bool "Enable 16-bit UID system calls" if EMBEDDED 688 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 689 default y 690 help 691 This enables the legacy 16-bit UID syscall wrappers. 692 693config SYSCTL_SYSCALL 694 bool "Sysctl syscall support" if EMBEDDED 695 default y 696 select SYSCTL 697 ---help--- 698 sys_sysctl uses binary paths that have been found challenging 699 to properly maintain and use. The interface in /proc/sys 700 using paths with ascii names is now the primary path to this 701 information. 702 703 Almost nothing using the binary sysctl interface so if you are 704 trying to save some space it is probably safe to disable this, 705 making your kernel marginally smaller. 706 707 If unsure say Y here. 708 709config KALLSYMS 710 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 711 default y 712 help 713 Say Y here to let the kernel print out symbolic crash information and 714 symbolic stack backtraces. This increases the size of the kernel 715 somewhat, as all symbols have to be loaded into the kernel image. 716 717config KALLSYMS_ALL 718 bool "Include all symbols in kallsyms" 719 depends on DEBUG_KERNEL && KALLSYMS 720 help 721 Normally kallsyms only contains the symbols of functions, for nicer 722 OOPS messages. Some debuggers can use kallsyms for other 723 symbols too: say Y here to include all symbols, if you need them 724 and you don't care about adding 300k to the size of your kernel. 725 726 Say N. 727 728config KALLSYMS_EXTRA_PASS 729 bool "Do an extra kallsyms pass" 730 depends on KALLSYMS 731 help 732 If kallsyms is not working correctly, the build will fail with 733 inconsistent kallsyms data. If that occurs, log a bug report and 734 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 735 Always say N here unless you find a bug in kallsyms, which must be 736 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 737 you wait for kallsyms to be fixed. 738 739 740config HOTPLUG 741 bool "Support for hot-pluggable devices" if EMBEDDED 742 default y 743 help 744 This option is provided for the case where no hotplug or uevent 745 capabilities is wanted by the kernel. You should only consider 746 disabling this option for embedded systems that do not use modules, a 747 dynamic /dev tree, or dynamic device discovery. Just say Y. 748 749config PRINTK 750 default y 751 bool "Enable support for printk" if EMBEDDED 752 help 753 This option enables normal printk support. Removing it 754 eliminates most of the message strings from the kernel image 755 and makes the kernel more or less silent. As this makes it 756 very difficult to diagnose system problems, saying N here is 757 strongly discouraged. 758 759config BUG 760 bool "BUG() support" if EMBEDDED 761 default y 762 help 763 Disabling this option eliminates support for BUG and WARN, reducing 764 the size of your kernel image and potentially quietly ignoring 765 numerous fatal conditions. You should only consider disabling this 766 option for embedded systems with no facilities for reporting errors. 767 Just say Y. 768 769config ELF_CORE 770 default y 771 bool "Enable ELF core dumps" if EMBEDDED 772 help 773 Enable support for generating core dumps. Disabling saves about 4k. 774 775config PCSPKR_PLATFORM 776 bool "Enable PC-Speaker support" if EMBEDDED 777 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES 778 default y 779 help 780 This option allows to disable the internal PC-Speaker 781 support, saving some memory. 782 783config COMPAT_BRK 784 bool "Disable heap randomization" 785 default y 786 help 787 Randomizing heap placement makes heap exploits harder, but it 788 also breaks ancient binaries (including anything libc5 based). 789 This option changes the bootup default to heap randomization 790 disabled, and can be overriden runtime by setting 791 /proc/sys/kernel/randomize_va_space to 2. 792 793 On non-ancient distros (post-2000 ones) N is usually a safe choice. 794 795config BASE_FULL 796 default y 797 bool "Enable full-sized data structures for core" if EMBEDDED 798 help 799 Disabling this option reduces the size of miscellaneous core 800 kernel data structures. This saves memory on small machines, 801 but may reduce performance. 802 803config FUTEX 804 bool "Enable futex support" if EMBEDDED 805 default y 806 select RT_MUTEXES 807 help 808 Disabling this option will cause the kernel to be built without 809 support for "fast userspace mutexes". The resulting kernel may not 810 run glibc-based applications correctly. 811 812config ANON_INODES 813 bool 814 815config EPOLL 816 bool "Enable eventpoll support" if EMBEDDED 817 default y 818 select ANON_INODES 819 help 820 Disabling this option will cause the kernel to be built without 821 support for epoll family of system calls. 822 823config SIGNALFD 824 bool "Enable signalfd() system call" if EMBEDDED 825 select ANON_INODES 826 default y 827 help 828 Enable the signalfd() system call that allows to receive signals 829 on a file descriptor. 830 831 If unsure, say Y. 832 833config TIMERFD 834 bool "Enable timerfd() system call" if EMBEDDED 835 select ANON_INODES 836 default y 837 help 838 Enable the timerfd() system call that allows to receive timer 839 events on a file descriptor. 840 841 If unsure, say Y. 842 843config EVENTFD 844 bool "Enable eventfd() system call" if EMBEDDED 845 select ANON_INODES 846 default y 847 help 848 Enable the eventfd() system call that allows to receive both 849 kernel notification (ie. KAIO) or userspace notifications. 850 851 If unsure, say Y. 852 853config SHMEM 854 bool "Use full shmem filesystem" if EMBEDDED 855 default y 856 depends on MMU 857 help 858 The shmem is an internal filesystem used to manage shared memory. 859 It is backed by swap and manages resource limits. It is also exported 860 to userspace as tmpfs if TMPFS is enabled. Disabling this 861 option replaces shmem and tmpfs with the much simpler ramfs code, 862 which may be appropriate on small systems without swap. 863 864config AIO 865 bool "Enable AIO support" if EMBEDDED 866 default y 867 help 868 This option enables POSIX asynchronous I/O which may by used 869 by some high performance threaded applications. Disabling 870 this option saves about 7k. 871 872config VM_EVENT_COUNTERS 873 default y 874 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 875 help 876 VM event counters are needed for event counts to be shown. 877 This option allows the disabling of the VM event counters 878 on EMBEDDED systems. /proc/vmstat will only show page counts 879 if VM event counters are disabled. 880 881config PCI_QUIRKS 882 default y 883 bool "Enable PCI quirk workarounds" if EMBEDDED 884 depends on PCI 885 help 886 This enables workarounds for various PCI chipset 887 bugs/quirks. Disable this only if your target machine is 888 unaffected by PCI quirks. 889 890config SLUB_DEBUG 891 default y 892 bool "Enable SLUB debugging support" if EMBEDDED 893 depends on SLUB && SYSFS 894 help 895 SLUB has extensive debug support features. Disabling these can 896 result in significant savings in code size. This also disables 897 SLUB sysfs support. /sys/slab will not exist and there will be 898 no support for cache validation etc. 899 900choice 901 prompt "Choose SLAB allocator" 902 default SLUB 903 help 904 This option allows to select a slab allocator. 905 906config SLAB 907 bool "SLAB" 908 help 909 The regular slab allocator that is established and known to work 910 well in all environments. It organizes cache hot objects in 911 per cpu and per node queues. 912 913config SLUB 914 bool "SLUB (Unqueued Allocator)" 915 help 916 SLUB is a slab allocator that minimizes cache line usage 917 instead of managing queues of cached objects (SLAB approach). 918 Per cpu caching is realized using slabs of objects instead 919 of queues of objects. SLUB can use memory efficiently 920 and has enhanced diagnostics. SLUB is the default choice for 921 a slab allocator. 922 923config SLOB 924 depends on EMBEDDED 925 bool "SLOB (Simple Allocator)" 926 help 927 SLOB replaces the stock allocator with a drastically simpler 928 allocator. SLOB is generally more space efficient but 929 does not perform as well on large systems. 930 931endchoice 932 933config PROFILING 934 bool "Profiling support (EXPERIMENTAL)" 935 help 936 Say Y here to enable the extended profiling support mechanisms used 937 by profilers such as OProfile. 938 939# 940# Place an empty function call at each tracepoint site. Can be 941# dynamically changed for a probe function. 942# 943config TRACEPOINTS 944 bool 945 946config MARKERS 947 bool "Activate markers" 948 depends on TRACEPOINTS 949 help 950 Place an empty function call at each marker site. Can be 951 dynamically changed for a probe function. 952 953source "arch/Kconfig" 954 955endmenu # General setup 956 957config HAVE_GENERIC_DMA_COHERENT 958 bool 959 default n 960 961config SLABINFO 962 bool 963 depends on PROC_FS 964 depends on SLAB || SLUB_DEBUG 965 default y 966 967config RT_MUTEXES 968 boolean 969 select PLIST 970 971config BASE_SMALL 972 int 973 default 0 if BASE_FULL 974 default 1 if !BASE_FULL 975 976menuconfig MODULES 977 bool "Enable loadable module support" 978 help 979 Kernel modules are small pieces of compiled code which can 980 be inserted in the running kernel, rather than being 981 permanently built into the kernel. You use the "modprobe" 982 tool to add (and sometimes remove) them. If you say Y here, 983 many parts of the kernel can be built as modules (by 984 answering M instead of Y where indicated): this is most 985 useful for infrequently used options which are not required 986 for booting. For more information, see the man pages for 987 modprobe, lsmod, modinfo, insmod and rmmod. 988 989 If you say Y here, you will need to run "make 990 modules_install" to put the modules under /lib/modules/ 991 where modprobe can find them (you may need to be root to do 992 this). 993 994 If unsure, say Y. 995 996if MODULES 997 998config MODULE_FORCE_LOAD 999 bool "Forced module loading" 1000 default n 1001 help 1002 Allow loading of modules without version information (ie. modprobe 1003 --force). Forced module loading sets the 'F' (forced) taint flag and 1004 is usually a really bad idea. 1005 1006config MODULE_UNLOAD 1007 bool "Module unloading" 1008 help 1009 Without this option you will not be able to unload any 1010 modules (note that some modules may not be unloadable 1011 anyway), which makes your kernel smaller, faster 1012 and simpler. If unsure, say Y. 1013 1014config MODULE_FORCE_UNLOAD 1015 bool "Forced module unloading" 1016 depends on MODULE_UNLOAD && EXPERIMENTAL 1017 help 1018 This option allows you to force a module to unload, even if the 1019 kernel believes it is unsafe: the kernel will remove the module 1020 without waiting for anyone to stop using it (using the -f option to 1021 rmmod). This is mainly for kernel developers and desperate users. 1022 If unsure, say N. 1023 1024config MODVERSIONS 1025 bool "Module versioning support" 1026 help 1027 Usually, you have to use modules compiled with your kernel. 1028 Saying Y here makes it sometimes possible to use modules 1029 compiled for different kernels, by adding enough information 1030 to the modules to (hopefully) spot any changes which would 1031 make them incompatible with the kernel you are running. If 1032 unsure, say N. 1033 1034config MODULE_SRCVERSION_ALL 1035 bool "Source checksum for all modules" 1036 help 1037 Modules which contain a MODULE_VERSION get an extra "srcversion" 1038 field inserted into their modinfo section, which contains a 1039 sum of the source files which made it. This helps maintainers 1040 see exactly which source was used to build a module (since 1041 others sometimes change the module source without updating 1042 the version). With this option, such a "srcversion" field 1043 will be created for all modules. If unsure, say N. 1044 1045endif # MODULES 1046 1047config INIT_ALL_POSSIBLE 1048 bool 1049 help 1050 Back when each arch used to define their own cpu_online_map and 1051 cpu_possible_map, some of them chose to initialize cpu_possible_map 1052 with all 1s, and others with all 0s. When they were centralised, 1053 it was better to provide this option than to break all the archs 1054 and have several arch maintainers persuing me down dark alleys. 1055 1056config STOP_MACHINE 1057 bool 1058 default y 1059 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 1060 help 1061 Need stop_machine() primitive. 1062 1063source "block/Kconfig" 1064 1065config PREEMPT_NOTIFIERS 1066 bool 1067 1068