180daa560SRoman Zippelconfig ARCH 280daa560SRoman Zippel string 380daa560SRoman Zippel option env="ARCH" 480daa560SRoman Zippel 580daa560SRoman Zippelconfig KERNELVERSION 680daa560SRoman Zippel string 780daa560SRoman Zippel option env="KERNELVERSION" 880daa560SRoman Zippel 9face4374SRoman Zippelconfig DEFCONFIG_LIST 10face4374SRoman Zippel string 11b2670eacSPaolo 'Blaisorblade' Giarrusso depends on !UML 12face4374SRoman Zippel option defconfig_list 13face4374SRoman Zippel default "/lib/modules/$UNAME_RELEASE/.config" 14face4374SRoman Zippel default "/etc/kernel-config" 15face4374SRoman Zippel default "/boot/config-$UNAME_RELEASE" 1673531905SSam Ravnborg default "$ARCH_DEFCONFIG" 17face4374SRoman Zippel default "arch/$ARCH/defconfig" 18face4374SRoman Zippel 19b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 20b99b87f7SPeter Oberparleiter bool 21b99b87f7SPeter Oberparleiter depends on !UML 22b99b87f7SPeter Oberparleiter 23e360adbeSPeter Zijlstraconfig HAVE_IRQ_WORK 24e360adbeSPeter Zijlstra bool 25e360adbeSPeter Zijlstra 26e360adbeSPeter Zijlstraconfig IRQ_WORK 27e360adbeSPeter Zijlstra bool 28e360adbeSPeter Zijlstra depends on HAVE_IRQ_WORK 29e360adbeSPeter Zijlstra 301dbdc6f1SDavid Daneyconfig BUILDTIME_EXTABLE_SORT 311dbdc6f1SDavid Daney bool 321dbdc6f1SDavid Daney 33ff0cfc66SAl Boldimenu "General setup" 341da177e4SLinus Torvalds 351da177e4SLinus Torvaldsconfig EXPERIMENTAL 361da177e4SLinus Torvalds bool "Prompt for development and/or incomplete code/drivers" 371da177e4SLinus Torvalds ---help--- 381da177e4SLinus Torvalds Some of the various things that Linux supports (such as network 391da177e4SLinus Torvalds drivers, file systems, network protocols, etc.) can be in a state 401da177e4SLinus Torvalds of development where the functionality, stability, or the level of 411da177e4SLinus Torvalds testing is not yet high enough for general use. This is usually 421da177e4SLinus Torvalds known as the "alpha-test" phase among developers. If a feature is 431da177e4SLinus Torvalds currently in alpha-test, then the developers usually discourage 441da177e4SLinus Torvalds uninformed widespread use of this feature by the general public to 451da177e4SLinus Torvalds avoid "Why doesn't this work?" type mail messages. However, active 461da177e4SLinus Torvalds testing and use of these systems is welcomed. Just be aware that it 471da177e4SLinus Torvalds may not meet the normal level of reliability or it may fail to work 481da177e4SLinus Torvalds in some special cases. Detailed bug reports from people familiar 491da177e4SLinus Torvalds with the kernel internals are usually welcomed by the developers 501da177e4SLinus Torvalds (before submitting bug reports, please read the documents 511da177e4SLinus Torvalds <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 521da177e4SLinus Torvalds <file:Documentation/BUG-HUNTING>, and 531da177e4SLinus Torvalds <file:Documentation/oops-tracing.txt> in the kernel source). 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds This option will also make obsoleted drivers available. These are 561da177e4SLinus Torvalds drivers that have been replaced by something else, and/or are 571da177e4SLinus Torvalds scheduled to be removed in a future kernel release. 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds Unless you intend to help test and develop a feature or driver that 601da177e4SLinus Torvalds falls into this category, or you have a situation that requires 611da177e4SLinus Torvalds using these features, you should probably say N here, which will 621da177e4SLinus Torvalds cause the configurator to present you with fewer choices. If 631da177e4SLinus Torvalds you say Y here, you will be offered the choice of using features or 641da177e4SLinus Torvalds drivers that are currently considered to be in the alpha-test phase. 651da177e4SLinus Torvalds 661da177e4SLinus Torvaldsconfig BROKEN 671da177e4SLinus Torvalds bool 681da177e4SLinus Torvalds 691da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 701da177e4SLinus Torvalds bool 711da177e4SLinus Torvalds depends on BROKEN || !SMP 721da177e4SLinus Torvalds default y 731da177e4SLinus Torvalds 741da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 751da177e4SLinus Torvalds int 76dd673bcaSAdrian Bunk default 32 if !UML 77dd673bcaSAdrian Bunk default 128 if UML 781da177e4SLinus Torvalds help 7934ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 8034ad92c2SRandy Dunlap variables passed to init from the kernel command line. 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds 8384336466SRoland McGrathconfig CROSS_COMPILE 8484336466SRoland McGrath string "Cross-compiler tool prefix" 8584336466SRoland McGrath help 8684336466SRoland McGrath Same as running 'make CROSS_COMPILE=prefix-' but stored for 8784336466SRoland McGrath default make runs in this kernel build directory. You don't 8884336466SRoland McGrath need to set this unless you want the configured kernel build 8984336466SRoland McGrath directory to select the cross-compiler automatically. 9084336466SRoland McGrath 911da177e4SLinus Torvaldsconfig LOCALVERSION 921da177e4SLinus Torvalds string "Local version - append to kernel release" 931da177e4SLinus Torvalds help 941da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 951da177e4SLinus Torvalds This will show up when you type uname, for example. 961da177e4SLinus Torvalds The string you set here will be appended after the contents of 971da177e4SLinus Torvalds any files with a filename matching localversion* in your 981da177e4SLinus Torvalds object and source tree, in that order. Your total string can 991da177e4SLinus Torvalds be a maximum of 64 characters. 1001da177e4SLinus Torvalds 101aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 102aaebf433SRyan Anderson bool "Automatically append version information to the version string" 103aaebf433SRyan Anderson default y 104aaebf433SRyan Anderson help 105aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 1066e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 1076e5a5420SRobert P. J. Day top of tree revision. 108aaebf433SRyan Anderson 109aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 1106e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 111aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 1126e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 113aaebf433SRyan Anderson 1146e5a5420SRobert P. J. Day (The actual string used here is the first eight characters produced 1156e5a5420SRobert P. J. Day by running the command: 1166e5a5420SRobert P. J. Day 1176e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 1186e5a5420SRobert P. J. Day 1196e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 120aaebf433SRyan Anderson 1212e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 1222e9f3bddSH. Peter Anvin bool 1232e9f3bddSH. Peter Anvin 1242e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 1252e9f3bddSH. Peter Anvin bool 1262e9f3bddSH. Peter Anvin 1272e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 1282e9f3bddSH. Peter Anvin bool 1292e9f3bddSH. Peter Anvin 1303ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 1313ebe1243SLasse Collin bool 1323ebe1243SLasse Collin 1337dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 1347dd65febSAlbin Tonnerre bool 1357dd65febSAlbin Tonnerre 13630d65dbfSAlain Knaffchoice 13730d65dbfSAlain Knaff prompt "Kernel compression mode" 13830d65dbfSAlain Knaff default KERNEL_GZIP 1393ebe1243SLasse Collin depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO 14030d65dbfSAlain Knaff help 14130d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 14230d65dbfSAlain Knaff Several compression algorithms are available, which differ 14330d65dbfSAlain Knaff in efficiency, compression and decompression speed. 14430d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 14530d65dbfSAlain Knaff Decompression speed is relevant at each boot. 14630d65dbfSAlain Knaff 14730d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 14830d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 14930d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 15030d65dbfSAlain Knaff supplied by Christian Ludwig) 15130d65dbfSAlain Knaff 15230d65dbfSAlain Knaff High compression options are mostly useful for users, who 15330d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 15430d65dbfSAlain Knaff size matters less. 15530d65dbfSAlain Knaff 15630d65dbfSAlain Knaff If in doubt, select 'gzip' 15730d65dbfSAlain Knaff 15830d65dbfSAlain Knaffconfig KERNEL_GZIP 15930d65dbfSAlain Knaff bool "Gzip" 1602e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 16130d65dbfSAlain Knaff help 1627dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 1637dd65febSAlbin Tonnerre between compression ratio and decompression speed. 16430d65dbfSAlain Knaff 16530d65dbfSAlain Knaffconfig KERNEL_BZIP2 16630d65dbfSAlain Knaff bool "Bzip2" 1672e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 16830d65dbfSAlain Knaff help 16930d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 1700a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 1712e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 1722e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 1732e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 17430d65dbfSAlain Knaff 17530d65dbfSAlain Knaffconfig KERNEL_LZMA 17630d65dbfSAlain Knaff bool "LZMA" 1772e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 17830d65dbfSAlain Knaff help 1790a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 1800a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 1810a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 18230d65dbfSAlain Knaff 1833ebe1243SLasse Collinconfig KERNEL_XZ 1843ebe1243SLasse Collin bool "XZ" 1853ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 1863ebe1243SLasse Collin help 1873ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 1883ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 1893ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 1903ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 1913ebe1243SLasse Collin filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ 1923ebe1243SLasse Collin will create a few percent smaller kernel than plain LZMA. 1933ebe1243SLasse Collin 1943ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 1953ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 1963ebe1243SLasse Collin and LZO. Compression is slow. 1973ebe1243SLasse Collin 1987dd65febSAlbin Tonnerreconfig KERNEL_LZO 1997dd65febSAlbin Tonnerre bool "LZO" 2007dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 2017dd65febSAlbin Tonnerre help 2020a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 203681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 2047dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 2057dd65febSAlbin Tonnerre 20630d65dbfSAlain Knaffendchoice 20730d65dbfSAlain Knaff 208bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 209bd5dc17bSJosh Triplett string "Default hostname" 210bd5dc17bSJosh Triplett default "(none)" 211bd5dc17bSJosh Triplett help 212bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 213bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 214bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 215bd5dc17bSJosh Triplett system more usable with less configuration. 216bd5dc17bSJosh Triplett 2171da177e4SLinus Torvaldsconfig SWAP 2181da177e4SLinus Torvalds bool "Support for paging of anonymous memory (swap)" 2199361401eSDavid Howells depends on MMU && BLOCK 2201da177e4SLinus Torvalds default y 2211da177e4SLinus Torvalds help 2221da177e4SLinus Torvalds This option allows you to choose whether you want to have support 2231da177e4SLinus Torvalds for so called swap devices or swap files in your kernel that are 2241da177e4SLinus Torvalds used to provide more virtual memory than the actual RAM present 2251da177e4SLinus Torvalds in your computer. If unsure say Y. 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvaldsconfig SYSVIPC 2281da177e4SLinus Torvalds bool "System V IPC" 2291da177e4SLinus Torvalds ---help--- 2301da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 2311da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 2321da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 2331da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 2341da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 2351da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 2361da177e4SLinus Torvalds you'll need to say Y here. 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 2391da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 2401da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 2411da177e4SLinus Torvalds 242a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 243a5494dcdSEric W. Biederman bool 244a5494dcdSEric W. Biederman depends on SYSVIPC 245a5494dcdSEric W. Biederman depends on SYSCTL 246a5494dcdSEric W. Biederman default y 247a5494dcdSEric W. Biederman 2481da177e4SLinus Torvaldsconfig POSIX_MQUEUE 2491da177e4SLinus Torvalds bool "POSIX Message Queues" 2501da177e4SLinus Torvalds depends on NET && EXPERIMENTAL 2511da177e4SLinus Torvalds ---help--- 2521da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 2531da177e4SLinus Torvalds queues every message has a priority which decides about succession 2541da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 2551da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 256b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 2591da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 2601da177e4SLinus Torvalds operations on message queues. 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds If unsure, say Y. 2631da177e4SLinus Torvalds 264bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 265bdc8e5f8SSerge E. Hallyn bool 266bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 267bdc8e5f8SSerge E. Hallyn depends on SYSCTL 268bdc8e5f8SSerge E. Hallyn default y 269bdc8e5f8SSerge E. Hallyn 270990d6c2dSAneesh Kumar K.Vconfig FHANDLE 271990d6c2dSAneesh Kumar K.V bool "open by fhandle syscalls" 272990d6c2dSAneesh Kumar K.V select EXPORTFS 273990d6c2dSAneesh Kumar K.V help 274990d6c2dSAneesh Kumar K.V If you say Y here, a user level program will be able to map 275990d6c2dSAneesh Kumar K.V file names to handle and then later use the handle for 276990d6c2dSAneesh Kumar K.V different file system operations. This is useful in implementing 277990d6c2dSAneesh Kumar K.V userspace file servers, which now track files using handles instead 278990d6c2dSAneesh Kumar K.V of names. The handle would remain the same even if file names 279990d6c2dSAneesh Kumar K.V get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 280990d6c2dSAneesh Kumar K.V syscalls. 281990d6c2dSAneesh Kumar K.V 2821da177e4SLinus Torvaldsconfig AUDIT 2831da177e4SLinus Torvalds bool "Auditing support" 284804a6a49SChris Wright depends on NET 2851da177e4SLinus Torvalds help 2861da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 2871da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 2881da177e4SLinus Torvalds logging of avc messages output). Does not do system-call 2891da177e4SLinus Torvalds auditing without CONFIG_AUDITSYSCALL. 2901da177e4SLinus Torvalds 2911da177e4SLinus Torvaldsconfig AUDITSYSCALL 2921da177e4SLinus Torvalds bool "Enable system-call auditing support" 2938f827a14SWill Deacon depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) 2941da177e4SLinus Torvalds default y if SECURITY_SELINUX 2951da177e4SLinus Torvalds help 2961da177e4SLinus Torvalds Enable low-overhead system-call auditing infrastructure that 2971da177e4SLinus Torvalds can be used independently or with another kernel subsystem, 29867640b60SEric Paris such as SELinux. 2991da177e4SLinus Torvalds 300939a67fcSEric Parisconfig AUDIT_WATCH 301939a67fcSEric Paris def_bool y 302939a67fcSEric Paris depends on AUDITSYSCALL 303939a67fcSEric Paris select FSNOTIFY 3041da177e4SLinus Torvalds 30574c3cbe3SAl Viroconfig AUDIT_TREE 30674c3cbe3SAl Viro def_bool y 30763c882a0SEric Paris depends on AUDITSYSCALL 30828a3a7ebSEric Paris select FSNOTIFY 30974c3cbe3SAl Viro 310633b4545SEric Parisconfig AUDIT_LOGINUID_IMMUTABLE 311633b4545SEric Paris bool "Make audit loginuid immutable" 312633b4545SEric Paris depends on AUDIT 313633b4545SEric Paris help 314f429ee3bSLinus Torvalds The config option toggles if a task setting its loginuid requires 315633b4545SEric Paris CAP_SYS_AUDITCONTROL or if that task should require no special permissions 316633b4545SEric Paris but should instead only allow setting its loginuid if it was never 317633b4545SEric Paris previously set. On systems which use systemd or a similar central 318633b4545SEric Paris process to restart login services this should be set to true. On older 319633b4545SEric Paris systems in which an admin would typically have to directly stop and 320633b4545SEric Paris start processes this should be set to false. Setting this to true allows 321633b4545SEric Paris one to drop potentially dangerous capabilites from the login tasks, 322633b4545SEric Paris but may not be backwards compatible with older init systems. 323633b4545SEric Paris 324d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 325764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 326d9817ebeSThomas Gleixner 327*391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 328*391dc69cSFrederic Weisbecker 329*391dc69cSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 330*391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 331*391dc69cSFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING 332*391dc69cSFrederic Weisbecker default y if PPC64 333*391dc69cSFrederic Weisbecker help 334*391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 335*391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 336*391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 337*391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 338*391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 339*391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 340*391dc69cSFrederic Weisbecker systems. 341*391dc69cSFrederic Weisbecker 342*391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 343*391dc69cSFrederic Weisbecker bool "BSD Process Accounting" 344*391dc69cSFrederic Weisbecker help 345*391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 346*391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 347*391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 348*391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 349*391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 350*391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 351*391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 352*391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 353*391dc69cSFrederic Weisbecker information. This is generally a good idea, so say Y. 354*391dc69cSFrederic Weisbecker 355*391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 356*391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 357*391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 358*391dc69cSFrederic Weisbecker default n 359*391dc69cSFrederic Weisbecker help 360*391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 361*391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 362*391dc69cSFrederic Weisbecker process and it's parent. Note that this file format is incompatible 363*391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 364*391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 365*391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 366*391dc69cSFrederic Weisbecker 367*391dc69cSFrederic Weisbeckerconfig TASKSTATS 368*391dc69cSFrederic Weisbecker bool "Export task/process statistics through netlink (EXPERIMENTAL)" 369*391dc69cSFrederic Weisbecker depends on NET 370*391dc69cSFrederic Weisbecker default n 371*391dc69cSFrederic Weisbecker help 372*391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 373*391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 374*391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 375*391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 376*391dc69cSFrederic Weisbecker space on task exit. 377*391dc69cSFrederic Weisbecker 378*391dc69cSFrederic Weisbecker Say N if unsure. 379*391dc69cSFrederic Weisbecker 380*391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 381*391dc69cSFrederic Weisbecker bool "Enable per-task delay accounting (EXPERIMENTAL)" 382*391dc69cSFrederic Weisbecker depends on TASKSTATS 383*391dc69cSFrederic Weisbecker help 384*391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 385*391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 386*391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 387*391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 388*391dc69cSFrederic Weisbecker 389*391dc69cSFrederic Weisbecker Say N if unsure. 390*391dc69cSFrederic Weisbecker 391*391dc69cSFrederic Weisbeckerconfig TASK_XACCT 392*391dc69cSFrederic Weisbecker bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 393*391dc69cSFrederic Weisbecker depends on TASKSTATS 394*391dc69cSFrederic Weisbecker help 395*391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 396*391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 397*391dc69cSFrederic Weisbecker 398*391dc69cSFrederic Weisbecker Say N if unsure. 399*391dc69cSFrederic Weisbecker 400*391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 401*391dc69cSFrederic Weisbecker bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 402*391dc69cSFrederic Weisbecker depends on TASK_XACCT 403*391dc69cSFrederic Weisbecker help 404*391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 405*391dc69cSFrederic Weisbecker task has caused. 406*391dc69cSFrederic Weisbecker 407*391dc69cSFrederic Weisbecker Say N if unsure. 408*391dc69cSFrederic Weisbecker 409*391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 410*391dc69cSFrederic Weisbecker 411c903ff83SMike Travismenu "RCU Subsystem" 412c903ff83SMike Travis 413c903ff83SMike Travischoice 414c903ff83SMike Travis prompt "RCU Implementation" 41531c9a24eSPaul E. McKenney default TREE_RCU 416c903ff83SMike Travis 417c903ff83SMike Travisconfig TREE_RCU 418c903ff83SMike Travis bool "Tree-based hierarchical RCU" 419687d7a96SPaul E. McKenney depends on !PREEMPT && SMP 420c903ff83SMike Travis help 421c903ff83SMike Travis This option selects the RCU implementation that is 422c903ff83SMike Travis designed for very large SMP system with hundreds or 423c17ef453SPaul E. McKenney thousands of CPUs. It also scales down nicely to 424c17ef453SPaul E. McKenney smaller systems. 425c903ff83SMike Travis 426f41d911fSPaul E. McKenneyconfig TREE_PREEMPT_RCU 427a57eb940SPaul E. McKenney bool "Preemptible tree-based hierarchical RCU" 4288008e129SPaul E. McKenney depends on PREEMPT && SMP 429f41d911fSPaul E. McKenney help 430f41d911fSPaul E. McKenney This option selects the RCU implementation that is 431f41d911fSPaul E. McKenney designed for very large SMP systems with hundreds or 432f41d911fSPaul E. McKenney thousands of CPUs, but for which real-time response 433bbe3eae8SPaul E. McKenney is also required. It also scales down nicely to 434bbe3eae8SPaul E. McKenney smaller systems. 435f41d911fSPaul E. McKenney 4369b1d82faSPaul E. McKenneyconfig TINY_RCU 4379b1d82faSPaul E. McKenney bool "UP-only small-memory-footprint RCU" 4388008e129SPaul E. McKenney depends on !PREEMPT && !SMP 4399b1d82faSPaul E. McKenney help 4409b1d82faSPaul E. McKenney This option selects the RCU implementation that is 4419b1d82faSPaul E. McKenney designed for UP systems from which real-time response 4429b1d82faSPaul E. McKenney is not required. This option greatly reduces the 4439b1d82faSPaul E. McKenney memory footprint of RCU. 4449b1d82faSPaul E. McKenney 445a57eb940SPaul E. McKenneyconfig TINY_PREEMPT_RCU 446a57eb940SPaul E. McKenney bool "Preemptible UP-only small-memory-footprint RCU" 4478008e129SPaul E. McKenney depends on PREEMPT && !SMP 448a57eb940SPaul E. McKenney help 449a57eb940SPaul E. McKenney This option selects the RCU implementation that is designed 450a57eb940SPaul E. McKenney for real-time UP systems. This option greatly reduces the 451a57eb940SPaul E. McKenney memory footprint of RCU. 452a57eb940SPaul E. McKenney 453c903ff83SMike Travisendchoice 454c903ff83SMike Travis 455a57eb940SPaul E. McKenneyconfig PREEMPT_RCU 456a57eb940SPaul E. McKenney def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) 457a57eb940SPaul E. McKenney help 458a57eb940SPaul E. McKenney This option enables preemptible-RCU code that is common between 459a57eb940SPaul E. McKenney the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. 460a57eb940SPaul E. McKenney 461c903ff83SMike Travisconfig RCU_FANOUT 462c903ff83SMike Travis int "Tree-based hierarchical RCU fanout value" 463c903ff83SMike Travis range 2 64 if 64BIT 464c903ff83SMike Travis range 2 32 if !64BIT 465f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 466c903ff83SMike Travis default 64 if 64BIT 467c903ff83SMike Travis default 32 if !64BIT 468c903ff83SMike Travis help 469c903ff83SMike Travis This option controls the fanout of hierarchical implementations 470c903ff83SMike Travis of RCU, allowing RCU to work efficiently on machines with 4714d87ffadSPaul E. McKenney large numbers of CPUs. This value must be at least the fourth 4724d87ffadSPaul E. McKenney root of NR_CPUS, which allows NR_CPUS to be insanely large. 4734d87ffadSPaul E. McKenney The default value of RCU_FANOUT should be used for production 4744d87ffadSPaul E. McKenney systems, but if you are stress-testing the RCU implementation 4754d87ffadSPaul E. McKenney itself, small RCU_FANOUT values allow you to test large-system 4764d87ffadSPaul E. McKenney code paths on small(er) systems. 477c903ff83SMike Travis 478c903ff83SMike Travis Select a specific number if testing RCU itself. 479c903ff83SMike Travis Take the default if unsure. 480c903ff83SMike Travis 4818932a63dSPaul E. McKenneyconfig RCU_FANOUT_LEAF 4828932a63dSPaul E. McKenney int "Tree-based hierarchical RCU leaf-level fanout value" 4838932a63dSPaul E. McKenney range 2 RCU_FANOUT if 64BIT 4848932a63dSPaul E. McKenney range 2 RCU_FANOUT if !64BIT 4858932a63dSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 4868932a63dSPaul E. McKenney default 16 4878932a63dSPaul E. McKenney help 4888932a63dSPaul E. McKenney This option controls the leaf-level fanout of hierarchical 4898932a63dSPaul E. McKenney implementations of RCU, and allows trading off cache misses 4908932a63dSPaul E. McKenney against lock contention. Systems that synchronize their 4918932a63dSPaul E. McKenney scheduling-clock interrupts for energy-efficiency reasons will 4928932a63dSPaul E. McKenney want the default because the smaller leaf-level fanout keeps 4938932a63dSPaul E. McKenney lock contention levels acceptably low. Very large systems 4948932a63dSPaul E. McKenney (hundreds or thousands of CPUs) will instead want to set this 4958932a63dSPaul E. McKenney value to the maximum value possible in order to reduce the 4968932a63dSPaul E. McKenney number of cache misses incurred during RCU's grace-period 4978932a63dSPaul E. McKenney initialization. These systems tend to run CPU-bound, and thus 4988932a63dSPaul E. McKenney are not helped by synchronized interrupts, and thus tend to 4998932a63dSPaul E. McKenney skew them, which reduces lock contention enough that large 5008932a63dSPaul E. McKenney leaf-level fanouts work well. 5018932a63dSPaul E. McKenney 5028932a63dSPaul E. McKenney Select a specific number if testing RCU itself. 5038932a63dSPaul E. McKenney 5048932a63dSPaul E. McKenney Select the maximum permissible value for large systems. 5058932a63dSPaul E. McKenney 5068932a63dSPaul E. McKenney Take the default if unsure. 5078932a63dSPaul E. McKenney 508c903ff83SMike Travisconfig RCU_FANOUT_EXACT 509c903ff83SMike Travis bool "Disable tree-based hierarchical RCU auto-balancing" 510f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 511c903ff83SMike Travis default n 512c903ff83SMike Travis help 513c903ff83SMike Travis This option forces use of the exact RCU_FANOUT value specified, 514c903ff83SMike Travis regardless of imbalances in the hierarchy. This is useful for 515c903ff83SMike Travis testing RCU itself, and might one day be useful on systems with 516c903ff83SMike Travis strong NUMA behavior. 517c903ff83SMike Travis 518c903ff83SMike Travis Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 519c903ff83SMike Travis 520c903ff83SMike Travis Say N if unsure. 521c903ff83SMike Travis 5228bd93a2cSPaul E. McKenneyconfig RCU_FAST_NO_HZ 5238bd93a2cSPaul E. McKenney bool "Accelerate last non-dyntick-idle CPU's grace periods" 524b807fbffSPaul E. McKenney depends on NO_HZ && SMP 5258bd93a2cSPaul E. McKenney default n 5268bd93a2cSPaul E. McKenney help 5278bd93a2cSPaul E. McKenney This option causes RCU to attempt to accelerate grace periods 528b807fbffSPaul E. McKenney in order to allow CPUs to enter dynticks-idle state more 529b807fbffSPaul E. McKenney quickly. On the other hand, this option increases the overhead 530b807fbffSPaul E. McKenney of the dynticks-idle checking, particularly on systems with 531b807fbffSPaul E. McKenney large numbers of CPUs. 5328bd93a2cSPaul E. McKenney 5338bd93a2cSPaul E. McKenney Say Y if energy efficiency is critically important, particularly 5348bd93a2cSPaul E. McKenney if you have relatively few CPUs. 5358bd93a2cSPaul E. McKenney 5368bd93a2cSPaul E. McKenney Say N if you are unsure. 5378bd93a2cSPaul E. McKenney 538c903ff83SMike Travisconfig TREE_RCU_TRACE 539f41d911fSPaul E. McKenney def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) 540c903ff83SMike Travis select DEBUG_FS 541c903ff83SMike Travis help 542f41d911fSPaul E. McKenney This option provides tracing for the TREE_RCU and 543f41d911fSPaul E. McKenney TREE_PREEMPT_RCU implementations, permitting Makefile to 544f41d911fSPaul E. McKenney trivially select kernel/rcutree_trace.c. 545c903ff83SMike Travis 54624278d14SPaul E. McKenneyconfig RCU_BOOST 54724278d14SPaul E. McKenney bool "Enable RCU priority boosting" 54827f4d280SPaul E. McKenney depends on RT_MUTEXES && PREEMPT_RCU 54924278d14SPaul E. McKenney default n 55024278d14SPaul E. McKenney help 55124278d14SPaul E. McKenney This option boosts the priority of preempted RCU readers that 55224278d14SPaul E. McKenney block the current preemptible RCU grace period for too long. 55324278d14SPaul E. McKenney This option also prevents heavy loads from blocking RCU 55424278d14SPaul E. McKenney callback invocation for all flavors of RCU. 55524278d14SPaul E. McKenney 55624278d14SPaul E. McKenney Say Y here if you are working with real-time apps or heavy loads 55724278d14SPaul E. McKenney Say N here if you are unsure. 55824278d14SPaul E. McKenney 55924278d14SPaul E. McKenneyconfig RCU_BOOST_PRIO 56024278d14SPaul E. McKenney int "Real-time priority to boost RCU readers to" 56124278d14SPaul E. McKenney range 1 99 56224278d14SPaul E. McKenney depends on RCU_BOOST 56324278d14SPaul E. McKenney default 1 56424278d14SPaul E. McKenney help 565c9336643SPaul E. McKenney This option specifies the real-time priority to which long-term 566c9336643SPaul E. McKenney preempted RCU readers are to be boosted. If you are working 567c9336643SPaul E. McKenney with a real-time application that has one or more CPU-bound 568c9336643SPaul E. McKenney threads running at a real-time priority level, you should set 569c9336643SPaul E. McKenney RCU_BOOST_PRIO to a priority higher then the highest-priority 570c9336643SPaul E. McKenney real-time CPU-bound thread. The default RCU_BOOST_PRIO value 571c9336643SPaul E. McKenney of 1 is appropriate in the common case, which is real-time 572c9336643SPaul E. McKenney applications that do not have any CPU-bound threads. 573c9336643SPaul E. McKenney 574c9336643SPaul E. McKenney Some real-time applications might not have a single real-time 575c9336643SPaul E. McKenney thread that saturates a given CPU, but instead might have 576c9336643SPaul E. McKenney multiple real-time threads that, taken together, fully utilize 577c9336643SPaul E. McKenney that CPU. In this case, you should set RCU_BOOST_PRIO to 578c9336643SPaul E. McKenney a priority higher than the lowest-priority thread that is 579c9336643SPaul E. McKenney conspiring to prevent the CPU from running any non-real-time 580c9336643SPaul E. McKenney tasks. For example, if one thread at priority 10 and another 581c9336643SPaul E. McKenney thread at priority 5 are between themselves fully consuming 582c9336643SPaul E. McKenney the CPU time on a given CPU, then RCU_BOOST_PRIO should be 583c9336643SPaul E. McKenney set to priority 6 or higher. 58424278d14SPaul E. McKenney 58524278d14SPaul E. McKenney Specify the real-time priority, or take the default if unsure. 58624278d14SPaul E. McKenney 58724278d14SPaul E. McKenneyconfig RCU_BOOST_DELAY 58824278d14SPaul E. McKenney int "Milliseconds to delay boosting after RCU grace-period start" 58924278d14SPaul E. McKenney range 0 3000 59024278d14SPaul E. McKenney depends on RCU_BOOST 59124278d14SPaul E. McKenney default 500 59224278d14SPaul E. McKenney help 59324278d14SPaul E. McKenney This option specifies the time to wait after the beginning of 59424278d14SPaul E. McKenney a given grace period before priority-boosting preempted RCU 59524278d14SPaul E. McKenney readers blocking that grace period. Note that any RCU reader 59624278d14SPaul E. McKenney blocking an expedited RCU grace period is boosted immediately. 59724278d14SPaul E. McKenney 59824278d14SPaul E. McKenney Accept the default if unsure. 59924278d14SPaul E. McKenney 600c903ff83SMike Travisendmenu # "RCU Subsystem" 601c903ff83SMike Travis 6021da177e4SLinus Torvaldsconfig IKCONFIG 603f2443ab6SRoss Biro tristate "Kernel .config support" 6041da177e4SLinus Torvalds ---help--- 6051da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 6061da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 6071da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 6081da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 6091da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 6101da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 6111da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 6121da177e4SLinus Torvalds /proc/config.gz if enabled (below). 6131da177e4SLinus Torvalds 6141da177e4SLinus Torvaldsconfig IKCONFIG_PROC 6151da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 6161da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 6171da177e4SLinus Torvalds ---help--- 6181da177e4SLinus Torvalds This option enables access to the kernel configuration file 6191da177e4SLinus Torvalds through /proc/config.gz. 6201da177e4SLinus Torvalds 621794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 622794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 623794543a2SAlistair John Strachan range 12 21 624f17a32e9SAdrian Bunk default 17 625794543a2SAlistair John Strachan help 626794543a2SAlistair John Strachan Select kernel log buffer size as a power of 2. 627f17a32e9SAdrian Bunk Examples: 628f17a32e9SAdrian Bunk 17 => 128 KB 629f17a32e9SAdrian Bunk 16 => 64 KB 630f17a32e9SAdrian Bunk 15 => 32 KB 631f17a32e9SAdrian Bunk 14 => 16 KB 632794543a2SAlistair John Strachan 13 => 8 KB 633794543a2SAlistair John Strachan 12 => 4 KB 634794543a2SAlistair John Strachan 6355cdc38f9SKAMEZAWA Hiroyuki# 6365cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 6375cdc38f9SKAMEZAWA Hiroyuki# 6385cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 6395cdc38f9SKAMEZAWA Hiroyuki bool 6405cdc38f9SKAMEZAWA Hiroyuki 64123964d2dSLi Zefanmenuconfig CGROUPS 64223964d2dSLi Zefan boolean "Control Group support" 6430dea1168SKirill A. Shutemov depends on EVENTFD 644ddbcc7e8SPaul Menage help 64523964d2dSLi Zefan This option adds support for grouping sets of processes together, for 6465cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 6475cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 6485cdc38f9SKAMEZAWA Hiroyuki See 6495cdc38f9SKAMEZAWA Hiroyuki - Documentation/scheduler/sched-design-CFS.txt (CFS) 65045ce80fbSLi Zefan - Documentation/cgroups/ (features for grouping, isolation 65145ce80fbSLi Zefan and resource control) 652ddbcc7e8SPaul Menage 653ddbcc7e8SPaul Menage Say N if unsure. 654ddbcc7e8SPaul Menage 65523964d2dSLi Zefanif CGROUPS 65623964d2dSLi Zefan 657006cb992SPaul Menageconfig CGROUP_DEBUG 658006cb992SPaul Menage bool "Example debug cgroup subsystem" 659418d7d87SPaul Menage default n 660006cb992SPaul Menage help 661006cb992SPaul Menage This option enables a simple cgroup subsystem that 662006cb992SPaul Menage exports useful debugging information about the cgroups 66323964d2dSLi Zefan framework. 664006cb992SPaul Menage 66523964d2dSLi Zefan Say N if unsure. 666006cb992SPaul Menage 667dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER 66823964d2dSLi Zefan bool "Freezer cgroup subsystem" 669dc52ddc0SMatt Helsley help 670dc52ddc0SMatt Helsley Provides a way to freeze and unfreeze all tasks in a 671dc52ddc0SMatt Helsley cgroup. 672dc52ddc0SMatt Helsley 67308ce5f16SSerge E. Hallynconfig CGROUP_DEVICE 67408ce5f16SSerge E. Hallyn bool "Device controller for cgroups" 67508ce5f16SSerge E. Hallyn help 67608ce5f16SSerge E. Hallyn Provides a cgroup implementing whitelists for devices which 67708ce5f16SSerge E. Hallyn a process in the cgroup can mknod or open. 67808ce5f16SSerge E. Hallyn 6791da177e4SLinus Torvaldsconfig CPUSETS 6801da177e4SLinus Torvalds bool "Cpuset support" 6811da177e4SLinus Torvalds help 682d9fd8a6dSRandy Dunlap This option will let you create and manage CPUSETs which 6831da177e4SLinus Torvalds allow dynamically partitioning a system into sets of CPUs and 6841da177e4SLinus Torvalds Memory Nodes and assigning tasks to run only within those sets. 6851da177e4SLinus Torvalds This is primarily useful on large SMP or NUMA systems. 6861da177e4SLinus Torvalds 6871da177e4SLinus Torvalds Say N if unsure. 6881da177e4SLinus Torvalds 68923964d2dSLi Zefanconfig PROC_PID_CPUSET 69023964d2dSLi Zefan bool "Include legacy /proc/<pid>/cpuset file" 69123964d2dSLi Zefan depends on CPUSETS 69223964d2dSLi Zefan default y 69323964d2dSLi Zefan 694d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT 695d842de87SSrivatsa Vaddagiri bool "Simple CPU accounting cgroup subsystem" 696d842de87SSrivatsa Vaddagiri help 697d842de87SSrivatsa Vaddagiri Provides a simple Resource Controller for monitoring the 69823964d2dSLi Zefan total CPU consumed by the tasks in a cgroup. 699d842de87SSrivatsa Vaddagiri 700e552b661SPavel Emelianovconfig RESOURCE_COUNTERS 701e552b661SPavel Emelianov bool "Resource counters" 702e552b661SPavel Emelianov help 703e552b661SPavel Emelianov This option enables controller independent resource accounting 70423964d2dSLi Zefan infrastructure that works with cgroups. 705e552b661SPavel Emelianov 706c255a458SAndrew Mortonconfig MEMCG 70700f0b825SBalbir Singh bool "Memory Resource Controller for Control Groups" 70879ae9c29SDaniel Lezcano depends on RESOURCE_COUNTERS 709cf475ad2SBalbir Singh select MM_OWNER 71000f0b825SBalbir Singh help 71184ad6d70SKAMEZAWA Hiroyuki Provides a memory resource controller that manages both anonymous 71221acb9caSThadeu Lima de Souza Cascardo memory and page cache. (See Documentation/cgroups/memory.txt) 71300f0b825SBalbir Singh 71400f0b825SBalbir Singh Note that setting this option increases fixed memory overhead 71584ad6d70SKAMEZAWA Hiroyuki associated with each page of memory in the system. By this, 71684ad6d70SKAMEZAWA Hiroyuki 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 71784ad6d70SKAMEZAWA Hiroyuki usage tracking struct at boot. Total amount of this is printed out 71884ad6d70SKAMEZAWA Hiroyuki at boot. 71900f0b825SBalbir Singh 72000f0b825SBalbir Singh Only enable when you're ok with these trade offs and really 72184ad6d70SKAMEZAWA Hiroyuki sure you need the memory resource controller. Even when you enable 72284ad6d70SKAMEZAWA Hiroyuki this, you can set "cgroup_disable=memory" at your boot option to 72384ad6d70SKAMEZAWA Hiroyuki disable memory resource controller and you can avoid overheads. 724c9d5409fSLi Zefan (and lose benefits of memory resource controller) 72500f0b825SBalbir Singh 726cf475ad2SBalbir Singh This config option also selects MM_OWNER config option, which 727cf475ad2SBalbir Singh could in turn add some fork/exit overhead. 728cf475ad2SBalbir Singh 729c255a458SAndrew Mortonconfig MEMCG_SWAP 73065e0e811SKAMEZAWA Hiroyuki bool "Memory Resource Controller Swap Extension" 731c255a458SAndrew Morton depends on MEMCG && SWAP 732c077719bSKAMEZAWA Hiroyuki help 733c077719bSKAMEZAWA Hiroyuki Add swap management feature to memory resource controller. When you 734c077719bSKAMEZAWA Hiroyuki enable this, you can limit mem+swap usage per cgroup. In other words, 735c077719bSKAMEZAWA Hiroyuki when you disable this, memory resource controller has no cares to 736c077719bSKAMEZAWA Hiroyuki usage of swap...a process can exhaust all of the swap. This extension 737c077719bSKAMEZAWA Hiroyuki is useful when you want to avoid exhaustion swap but this itself 738c077719bSKAMEZAWA Hiroyuki adds more overheads and consumes memory for remembering information. 739c077719bSKAMEZAWA Hiroyuki Especially if you use 32bit system or small memory system, please 740c077719bSKAMEZAWA Hiroyuki be careful about enabling this. When memory resource controller 741c077719bSKAMEZAWA Hiroyuki is disabled by boot option, this will be automatically disabled and 742c077719bSKAMEZAWA Hiroyuki there will be no overhead from this. Even when you set this config=y, 74300a66d29SWANG Cong if boot option "swapaccount=0" is set, swap will not be accounted. 744627991a2SKAMEZAWA Hiroyuki Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page 745627991a2SKAMEZAWA Hiroyuki size is 4096bytes, 512k per 1Gbytes of swap. 746c255a458SAndrew Mortonconfig MEMCG_SWAP_ENABLED 747a42c390cSMichal Hocko bool "Memory Resource Controller Swap Extension enabled by default" 748c255a458SAndrew Morton depends on MEMCG_SWAP 749a42c390cSMichal Hocko default y 750a42c390cSMichal Hocko help 751a42c390cSMichal Hocko Memory Resource Controller Swap Extension comes with its price in 752a42c390cSMichal Hocko a bigger memory consumption. General purpose distribution kernels 75343d547f9SJim Cromie which want to enable the feature but keep it disabled by default 754a42c390cSMichal Hocko and let the user enable it by swapaccount boot command line 755a42c390cSMichal Hocko parameter should have this option unselected. 756a42c390cSMichal Hocko For those who want to have the feature enabled by default should 757a42c390cSMichal Hocko select this option (if, for some reason, they need to disable it 75800a66d29SWANG Cong then swapaccount=0 does the trick). 759c255a458SAndrew Mortonconfig MEMCG_KMEM 760e5671dfaSGlauber Costa bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)" 761c255a458SAndrew Morton depends on MEMCG && EXPERIMENTAL 762e5671dfaSGlauber Costa default n 763e5671dfaSGlauber Costa help 764e5671dfaSGlauber Costa The Kernel Memory extension for Memory Resource Controller can limit 765e5671dfaSGlauber Costa the amount of memory used by kernel objects in the system. Those are 766e5671dfaSGlauber Costa fundamentally different from the entities handled by the standard 767e5671dfaSGlauber Costa Memory Controller, which are page-based, and can be swapped. Users of 768e5671dfaSGlauber Costa the kmem extension can use it to guarantee that no group of processes 769e5671dfaSGlauber Costa will ever exhaust kernel resources alone. 770c077719bSKAMEZAWA Hiroyuki 7712bc64a20SAneesh Kumar K.Vconfig CGROUP_HUGETLB 7722bc64a20SAneesh Kumar K.V bool "HugeTLB Resource Controller for Control Groups" 7732bc64a20SAneesh Kumar K.V depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL 7742bc64a20SAneesh Kumar K.V default n 7752bc64a20SAneesh Kumar K.V help 7762bc64a20SAneesh Kumar K.V Provides a cgroup Resource Controller for HugeTLB pages. 7772bc64a20SAneesh Kumar K.V When you enable this, you can put a per cgroup limit on HugeTLB usage. 7782bc64a20SAneesh Kumar K.V The limit is enforced during page fault. Since HugeTLB doesn't 7792bc64a20SAneesh Kumar K.V support page reclaim, enforcing the limit at page fault time implies 7802bc64a20SAneesh Kumar K.V that, the application will get SIGBUS signal if it tries to access 7812bc64a20SAneesh Kumar K.V HugeTLB pages beyond its limit. This requires the application to know 7822bc64a20SAneesh Kumar K.V beforehand how much HugeTLB pages it would require for its use. The 7832bc64a20SAneesh Kumar K.V control group is tracked in the third page lru pointer. This means 7842bc64a20SAneesh Kumar K.V that we cannot use the controller with huge page less than 3 pages. 7852bc64a20SAneesh Kumar K.V 786e5d1367fSStephane Eranianconfig CGROUP_PERF 787e5d1367fSStephane Eranian bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" 788e5d1367fSStephane Eranian depends on PERF_EVENTS && CGROUPS 789e5d1367fSStephane Eranian help 790e5d1367fSStephane Eranian This option extends the per-cpu mode to restrict monitoring to 7912d0f2520SLi Zefan threads which belong to the cgroup specified and run on the 792e5d1367fSStephane Eranian designated cpu. 793e5d1367fSStephane Eranian 794e5d1367fSStephane Eranian Say N if unsure. 795e5d1367fSStephane Eranian 7967c941438SDhaval Gianimenuconfig CGROUP_SCHED 7977c941438SDhaval Giani bool "Group CPU scheduler" 7987c941438SDhaval Giani default n 7997c941438SDhaval Giani help 8007c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 8017c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 8027c941438SDhaval Giani tasks. 8037c941438SDhaval Giani 8047c941438SDhaval Gianiif CGROUP_SCHED 8057c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 8067c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 8077c941438SDhaval Giani depends on CGROUP_SCHED 8087c941438SDhaval Giani default CGROUP_SCHED 8097c941438SDhaval Giani 810ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 811ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 812ab84d31eSPaul Turner depends on EXPERIMENTAL 813ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 814ab84d31eSPaul Turner default n 815ab84d31eSPaul Turner help 816ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 817ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 818ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 819ab84d31eSPaul Turner restriction. 820ab84d31eSPaul Turner See tip/Documentation/scheduler/sched-bwc.txt for more information. 821ab84d31eSPaul Turner 8227c941438SDhaval Gianiconfig RT_GROUP_SCHED 8237c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 8247c941438SDhaval Giani depends on EXPERIMENTAL 8257c941438SDhaval Giani depends on CGROUP_SCHED 8267c941438SDhaval Giani default n 8277c941438SDhaval Giani help 8287c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 82932bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 8307c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 8317c941438SDhaval Giani realtime bandwidth for them. 8327c941438SDhaval Giani See Documentation/scheduler/sched-rt-group.txt for more information. 8337c941438SDhaval Giani 8347c941438SDhaval Gianiendif #CGROUP_SCHED 8357c941438SDhaval Giani 836afc24d49SVivek Goyalconfig BLK_CGROUP 83732e380aeSTejun Heo bool "Block IO controller" 83879ae9c29SDaniel Lezcano depends on BLOCK 839afc24d49SVivek Goyal default n 840afc24d49SVivek Goyal ---help--- 841afc24d49SVivek Goyal Generic block IO controller cgroup interface. This is the common 842afc24d49SVivek Goyal cgroup interface which should be used by various IO controlling 843afc24d49SVivek Goyal policies. 844afc24d49SVivek Goyal 845afc24d49SVivek Goyal Currently, CFQ IO scheduler uses it to recognize task groups and 846afc24d49SVivek Goyal control disk bandwidth allocation (proportional time slice allocation) 847e43473b7SVivek Goyal to such task groups. It is also used by bio throttling logic in 848e43473b7SVivek Goyal block layer to implement upper limit in IO rates on a device. 849afc24d49SVivek Goyal 850afc24d49SVivek Goyal This option only enables generic Block IO controller infrastructure. 851e43473b7SVivek Goyal One needs to also enable actual IO controlling logic/policy. For 85279e2e759SMichael Witten enabling proportional weight division of disk bandwidth in CFQ, set 85379e2e759SMichael Witten CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 854c5e0591aSMichael Witten CONFIG_BLK_DEV_THROTTLING=y. 855afc24d49SVivek Goyal 856afc24d49SVivek Goyal See Documentation/cgroups/blkio-controller.txt for more information. 857afc24d49SVivek Goyal 858afc24d49SVivek Goyalconfig DEBUG_BLK_CGROUP 859afc24d49SVivek Goyal bool "Enable Block IO controller debugging" 860afc24d49SVivek Goyal depends on BLK_CGROUP 861afc24d49SVivek Goyal default n 862afc24d49SVivek Goyal ---help--- 863afc24d49SVivek Goyal Enable some debugging help. Currently it exports additional stat 864afc24d49SVivek Goyal files in a cgroup which can be useful for debugging. 865afc24d49SVivek Goyal 86623964d2dSLi Zefanendif # CGROUPS 867c077719bSKAMEZAWA Hiroyuki 868067bce1aSCyrill Gorcunovconfig CHECKPOINT_RESTORE 869067bce1aSCyrill Gorcunov bool "Checkpoint/restore support" if EXPERT 870067bce1aSCyrill Gorcunov default n 871067bce1aSCyrill Gorcunov help 872067bce1aSCyrill Gorcunov Enables additional kernel features in a sake of checkpoint/restore. 873067bce1aSCyrill Gorcunov In particular it adds auxiliary prctl codes to setup process text, 874067bce1aSCyrill Gorcunov data and heap segment sizes, and a few additional /proc filesystem 875067bce1aSCyrill Gorcunov entries. 876067bce1aSCyrill Gorcunov 877067bce1aSCyrill Gorcunov If unsure, say N here. 878067bce1aSCyrill Gorcunov 8798dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 8806a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 8816a108a14SDavid Rientjes default !EXPERT 882c5289a69SPavel Emelyanov help 883c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 884c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 885c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 886c5289a69SPavel Emelyanov different namespaces. 887c5289a69SPavel Emelyanov 8888dd2a82cSDaniel Lezcanoif NAMESPACES 8898dd2a82cSDaniel Lezcano 89058bfdd6dSPavel Emelyanovconfig UTS_NS 89158bfdd6dSPavel Emelyanov bool "UTS namespace" 89217a6d441SDaniel Lezcano default y 89358bfdd6dSPavel Emelyanov help 89458bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 89558bfdd6dSPavel Emelyanov uname() system call 89658bfdd6dSPavel Emelyanov 897ae5e1b22SPavel Emelyanovconfig IPC_NS 898ae5e1b22SPavel Emelyanov bool "IPC namespace" 8998dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 90017a6d441SDaniel Lezcano default y 901ae5e1b22SPavel Emelyanov help 902ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 903614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 904ae5e1b22SPavel Emelyanov 905aee16ce7SPavel Emelyanovconfig USER_NS 906aee16ce7SPavel Emelyanov bool "User namespace (EXPERIMENTAL)" 9078dd2a82cSDaniel Lezcano depends on EXPERIMENTAL 908e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 9095673a94cSEric W. Biederman select UIDGID_STRICT_TYPE_CHECKS 910e1c972b6SEric W. Biederman 9115673a94cSEric W. Biederman default n 912aee16ce7SPavel Emelyanov help 913aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 914aee16ce7SPavel Emelyanov to provide different user info for different servers. 915aee16ce7SPavel Emelyanov If unsure, say N. 916aee16ce7SPavel Emelyanov 91774bd59bbSPavel Emelyanovconfig PID_NS 9189bd38c2cSDaniel Lezcano bool "PID Namespaces" 91917a6d441SDaniel Lezcano default y 92074bd59bbSPavel Emelyanov help 92112d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 922692105b8SMatt LaPlante processes with the same pid as long as they are in different 92374bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 92474bd59bbSPavel Emelyanov 925d6eb633fSMatt Helsleyconfig NET_NS 926d6eb633fSMatt Helsley bool "Network namespace" 9278dd2a82cSDaniel Lezcano depends on NET 92817a6d441SDaniel Lezcano default y 929d6eb633fSMatt Helsley help 930d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 931d6eb633fSMatt Helsley of the network stack. 932d6eb633fSMatt Helsley 9338dd2a82cSDaniel Lezcanoendif # NAMESPACES 9348dd2a82cSDaniel Lezcano 935e1c972b6SEric W. Biedermanconfig UIDGID_CONVERTED 936e1c972b6SEric W. Biederman # True if all of the selected software conmponents are known 937e1c972b6SEric W. Biederman # to have uid_t and gid_t converted to kuid_t and kgid_t 938e1c972b6SEric W. Biederman # where appropriate and are otherwise safe to use with 939e1c972b6SEric W. Biederman # the user namespace. 940e1c972b6SEric W. Biederman bool 941e1c972b6SEric W. Biederman default y 942e1c972b6SEric W. Biederman 943e1c972b6SEric W. Biederman # List of kernel pieces that need user namespace work 944e1c972b6SEric W. Biederman # Features 945e1c972b6SEric W. Biederman depends on SYSVIPC = n 946e1c972b6SEric W. Biederman depends on IMA = n 947e1c972b6SEric W. Biederman depends on EVM = n 948e1c972b6SEric W. Biederman depends on KEYS = n 949e1c972b6SEric W. Biederman depends on AUDIT = n 950e1c972b6SEric W. Biederman depends on AUDITSYSCALL = n 951e1c972b6SEric W. Biederman depends on TASKSTATS = n 952e1c972b6SEric W. Biederman depends on TRACING = n 953e1c972b6SEric W. Biederman depends on FS_POSIX_ACL = n 954e1c972b6SEric W. Biederman depends on QUOTA = n 955e1c972b6SEric W. Biederman depends on QUOTACTL = n 956e1c972b6SEric W. Biederman depends on DEBUG_CREDENTIALS = n 957e1c972b6SEric W. Biederman depends on BSD_PROCESS_ACCT = n 958e1c972b6SEric W. Biederman depends on DRM = n 959e1c972b6SEric W. Biederman depends on PROC_EVENTS = n 960e1c972b6SEric W. Biederman 961e1c972b6SEric W. Biederman # Networking 962e1c972b6SEric W. Biederman depends on NET = n 963e1c972b6SEric W. Biederman depends on NET_9P = n 964e1c972b6SEric W. Biederman depends on IPX = n 965e1c972b6SEric W. Biederman depends on PHONET = n 966e1c972b6SEric W. Biederman depends on NET_CLS_FLOW = n 967e1c972b6SEric W. Biederman depends on NETFILTER_XT_MATCH_OWNER = n 968e1c972b6SEric W. Biederman depends on NETFILTER_XT_MATCH_RECENT = n 969e1c972b6SEric W. Biederman depends on NETFILTER_XT_TARGET_LOG = n 970e1c972b6SEric W. Biederman depends on NETFILTER_NETLINK_LOG = n 971e1c972b6SEric W. Biederman depends on INET = n 972e1c972b6SEric W. Biederman depends on IPV6 = n 973e1c972b6SEric W. Biederman depends on IP_SCTP = n 974e1c972b6SEric W. Biederman depends on AF_RXRPC = n 975e1c972b6SEric W. Biederman depends on LLC2 = n 976e1c972b6SEric W. Biederman depends on NET_KEY = n 977e1c972b6SEric W. Biederman depends on INET_DIAG = n 978e1c972b6SEric W. Biederman depends on DNS_RESOLVER = n 979e1c972b6SEric W. Biederman depends on AX25 = n 980e1c972b6SEric W. Biederman depends on ATALK = n 981e1c972b6SEric W. Biederman 982e1c972b6SEric W. Biederman # Filesystems 983e1c972b6SEric W. Biederman depends on USB_DEVICEFS = n 984e1c972b6SEric W. Biederman depends on USB_GADGETFS = n 985e1c972b6SEric W. Biederman depends on USB_FUNCTIONFS = n 986e1c972b6SEric W. Biederman depends on DEVTMPFS = n 987e1c972b6SEric W. Biederman depends on XENFS = n 988e1c972b6SEric W. Biederman 989e1c972b6SEric W. Biederman depends on 9P_FS = n 990e1c972b6SEric W. Biederman depends on ADFS_FS = n 991e1c972b6SEric W. Biederman depends on AFFS_FS = n 992e1c972b6SEric W. Biederman depends on AFS_FS = n 993e1c972b6SEric W. Biederman depends on AUTOFS4_FS = n 994e1c972b6SEric W. Biederman depends on BEFS_FS = n 995e1c972b6SEric W. Biederman depends on BFS_FS = n 996e1c972b6SEric W. Biederman depends on BTRFS_FS = n 997e1c972b6SEric W. Biederman depends on CEPH_FS = n 998e1c972b6SEric W. Biederman depends on CIFS = n 999e1c972b6SEric W. Biederman depends on CODA_FS = n 1000e1c972b6SEric W. Biederman depends on CONFIGFS_FS = n 1001e1c972b6SEric W. Biederman depends on CRAMFS = n 1002e1c972b6SEric W. Biederman depends on DEBUG_FS = n 1003e1c972b6SEric W. Biederman depends on ECRYPT_FS = n 1004e1c972b6SEric W. Biederman depends on EFS_FS = n 1005e1c972b6SEric W. Biederman depends on EXOFS_FS = n 1006e1c972b6SEric W. Biederman depends on FAT_FS = n 1007e1c972b6SEric W. Biederman depends on FUSE_FS = n 1008e1c972b6SEric W. Biederman depends on GFS2_FS = n 1009e1c972b6SEric W. Biederman depends on HFS_FS = n 1010e1c972b6SEric W. Biederman depends on HFSPLUS_FS = n 1011e1c972b6SEric W. Biederman depends on HPFS_FS = n 1012e1c972b6SEric W. Biederman depends on HUGETLBFS = n 1013e1c972b6SEric W. Biederman depends on ISO9660_FS = n 1014e1c972b6SEric W. Biederman depends on JFFS2_FS = n 1015e1c972b6SEric W. Biederman depends on JFS_FS = n 1016e1c972b6SEric W. Biederman depends on LOGFS = n 1017e1c972b6SEric W. Biederman depends on MINIX_FS = n 1018e1c972b6SEric W. Biederman depends on NCP_FS = n 1019e1c972b6SEric W. Biederman depends on NFSD = n 1020e1c972b6SEric W. Biederman depends on NFS_FS = n 1021e1c972b6SEric W. Biederman depends on NILFS2_FS = n 1022e1c972b6SEric W. Biederman depends on NTFS_FS = n 1023e1c972b6SEric W. Biederman depends on OCFS2_FS = n 1024e1c972b6SEric W. Biederman depends on OMFS_FS = n 1025e1c972b6SEric W. Biederman depends on QNX4FS_FS = n 1026e1c972b6SEric W. Biederman depends on QNX6FS_FS = n 1027e1c972b6SEric W. Biederman depends on REISERFS_FS = n 1028e1c972b6SEric W. Biederman depends on SQUASHFS = n 1029e1c972b6SEric W. Biederman depends on SYSV_FS = n 1030e1c972b6SEric W. Biederman depends on UBIFS_FS = n 1031e1c972b6SEric W. Biederman depends on UDF_FS = n 1032e1c972b6SEric W. Biederman depends on UFS_FS = n 1033e1c972b6SEric W. Biederman depends on VXFS_FS = n 1034e1c972b6SEric W. Biederman depends on XFS_FS = n 1035e1c972b6SEric W. Biederman 1036e1c972b6SEric W. Biederman depends on !UML || HOSTFS = n 1037e1c972b6SEric W. Biederman 1038e1c972b6SEric W. Biederman # The rare drivers that won't build 1039e1c972b6SEric W. Biederman depends on AIRO = n 1040e1c972b6SEric W. Biederman depends on AIRO_CS = n 1041e1c972b6SEric W. Biederman depends on TUN = n 1042e1c972b6SEric W. Biederman depends on INFINIBAND_QIB = n 1043e1c972b6SEric W. Biederman depends on BLK_DEV_LOOP = n 1044e1c972b6SEric W. Biederman depends on ANDROID_BINDER_IPC = n 1045e1c972b6SEric W. Biederman 1046e1c972b6SEric W. Biederman # Security modules 1047e1c972b6SEric W. Biederman depends on SECURITY_TOMOYO = n 1048e1c972b6SEric W. Biederman depends on SECURITY_APPARMOR = n 1049e1c972b6SEric W. Biederman 10505673a94cSEric W. Biedermanconfig UIDGID_STRICT_TYPE_CHECKS 10515673a94cSEric W. Biederman bool "Require conversions between uid/gids and their internal representation" 1052e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 10535673a94cSEric W. Biederman default n 10545673a94cSEric W. Biederman help 10555673a94cSEric W. Biederman While the nececessary conversions are being added to all subsystems this option allows 10565673a94cSEric W. Biederman the code to continue to build for unconverted subsystems. 10575673a94cSEric W. Biederman 10585673a94cSEric W. Biederman Say Y here if you want the strict type checking enabled 10595673a94cSEric W. Biederman 10605091faa4SMike Galbraithconfig SCHED_AUTOGROUP 10615091faa4SMike Galbraith bool "Automatic process group scheduling" 10625091faa4SMike Galbraith select EVENTFD 10635091faa4SMike Galbraith select CGROUPS 10645091faa4SMike Galbraith select CGROUP_SCHED 10655091faa4SMike Galbraith select FAIR_GROUP_SCHED 10665091faa4SMike Galbraith help 10675091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 10685091faa4SMike Galbraith automatically creating and populating task groups. This separation 10695091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 10705091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 10715091faa4SMike Galbraith upon task session. 10725091faa4SMike Galbraith 10737af37becSDaniel Lezcanoconfig MM_OWNER 10747af37becSDaniel Lezcano bool 10757af37becSDaniel Lezcano 10767af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED 10775d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features to support old userspace tools" 10787af37becSDaniel Lezcano depends on SYSFS 10797af37becSDaniel Lezcano default n 10807af37becSDaniel Lezcano help 10817af37becSDaniel Lezcano This option adds code that switches the layout of the "block" class 10827af37becSDaniel Lezcano devices, to not show up in /sys/class/block/, but only in 10837af37becSDaniel Lezcano /sys/block/. 10847af37becSDaniel Lezcano 10857af37becSDaniel Lezcano This switch is only active when the sysfs.deprecated=1 boot option is 10867af37becSDaniel Lezcano passed or the SYSFS_DEPRECATED_V2 option is set. 10877af37becSDaniel Lezcano 10887af37becSDaniel Lezcano This option allows new kernels to run on old distributions and tools, 10897af37becSDaniel Lezcano which might get confused by /sys/class/block/. Since 2007/2008 all 10907af37becSDaniel Lezcano major distributions and tools handle this just fine. 10917af37becSDaniel Lezcano 10927af37becSDaniel Lezcano Recent distributions and userspace tools after 2009/2010 depend on 10937af37becSDaniel Lezcano the existence of /sys/class/block/, and will not work with this 10947af37becSDaniel Lezcano option enabled. 10957af37becSDaniel Lezcano 10967af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 10977af37becSDaniel Lezcano need to say Y here. 10987af37becSDaniel Lezcano 10997af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED_V2 11005d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features by default" 11017af37becSDaniel Lezcano default n 11027af37becSDaniel Lezcano depends on SYSFS 11037af37becSDaniel Lezcano depends on SYSFS_DEPRECATED 11047af37becSDaniel Lezcano help 11057af37becSDaniel Lezcano Enable deprecated sysfs by default. 11067af37becSDaniel Lezcano 11077af37becSDaniel Lezcano See the CONFIG_SYSFS_DEPRECATED option for more details about this 11087af37becSDaniel Lezcano option. 11097af37becSDaniel Lezcano 11107af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 11117af37becSDaniel Lezcano need to say Y here. Even then, odds are you would not need it 11127af37becSDaniel Lezcano enabled, you can always pass the boot option if absolutely necessary. 11137af37becSDaniel Lezcano 11147af37becSDaniel Lezcanoconfig RELAY 11157af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 11167af37becSDaniel Lezcano help 11177af37becSDaniel Lezcano This option enables support for relay interface support in 11187af37becSDaniel Lezcano certain file systems (such as debugfs). 11197af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 11207af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 11217af37becSDaniel Lezcano user space. 11227af37becSDaniel Lezcano 11237af37becSDaniel Lezcano If unsure, say N. 11247af37becSDaniel Lezcano 1125f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1126f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1127f991633dSDimitri Gorokhovik depends on BROKEN || !FRV 1128f991633dSDimitri Gorokhovik help 1129f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1130f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1131f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1132f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 1133f991633dSDimitri Gorokhovik etc. See <file:Documentation/initrd.txt> for details. 1134f991633dSDimitri Gorokhovik 1135f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1136f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1137f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1138f991633dSDimitri Gorokhovik 1139f991633dSDimitri Gorokhovik If unsure say Y. 1140f991633dSDimitri Gorokhovik 1141c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1142c33df4eaSJean-Paul Saman 1143dbec4866SSam Ravnborgsource "usr/Kconfig" 1144dbec4866SSam Ravnborg 1145c33df4eaSJean-Paul Samanendif 1146c33df4eaSJean-Paul Saman 1147c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 114896fffeb4SIngo Molnar bool "Optimize for size" 1149c45b4f1fSLinus Torvalds help 1150c45b4f1fSLinus Torvalds Enabling this option will pass "-Os" instead of "-O2" to gcc 1151c45b4f1fSLinus Torvalds resulting in a smaller kernel. 1152c45b4f1fSLinus Torvalds 1153775a7229Sjkacur If unsure, say Y. 1154c45b4f1fSLinus Torvalds 11550847062aSRandy Dunlapconfig SYSCTL 11560847062aSRandy Dunlap bool 11570847062aSRandy Dunlap 1158b943c460SRandy Dunlapconfig ANON_INODES 1159b943c460SRandy Dunlap bool 1160b943c460SRandy Dunlap 11616a108a14SDavid Rientjesmenuconfig EXPERT 11626a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1163f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1164f505c553SJosh Triplett select DEBUG_KERNEL 11651da177e4SLinus Torvalds help 11661da177e4SLinus Torvalds This option allows certain base kernel options and settings 11671da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 11681da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 11691da177e4SLinus Torvalds Only use this if you really know what you are doing. 11701da177e4SLinus Torvalds 1171ae81f9e3SChuck Ebbertconfig UID16 11726a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 117309337f50SDavid S. Miller depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 1174ae81f9e3SChuck Ebbert default y 1175ae81f9e3SChuck Ebbert help 1176ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1177ae81f9e3SChuck Ebbert 1178b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL 11796a108a14SDavid Rientjes bool "Sysctl syscall support" if EXPERT 118026a7034bSEric W. Biederman depends on PROC_SYSCTL 1181c736de60SWANG Cong default n 1182b89a8171SEric W. Biederman select SYSCTL 1183b89a8171SEric W. Biederman ---help--- 118413bb7e37SEric W. Biederman sys_sysctl uses binary paths that have been found challenging 118513bb7e37SEric W. Biederman to properly maintain and use. The interface in /proc/sys 118613bb7e37SEric W. Biederman using paths with ascii names is now the primary path to this 118713bb7e37SEric W. Biederman information. 1188b89a8171SEric W. Biederman 118913bb7e37SEric W. Biederman Almost nothing using the binary sysctl interface so if you are 119013bb7e37SEric W. Biederman trying to save some space it is probably safe to disable this, 119113bb7e37SEric W. Biederman making your kernel marginally smaller. 1192b89a8171SEric W. Biederman 1193c736de60SWANG Cong If unsure say N here. 1194ae81f9e3SChuck Ebbert 11951da177e4SLinus Torvaldsconfig KALLSYMS 11966a108a14SDavid Rientjes bool "Load all symbols for debugging/ksymoops" if EXPERT 11971da177e4SLinus Torvalds default y 11981da177e4SLinus Torvalds help 11991da177e4SLinus Torvalds Say Y here to let the kernel print out symbolic crash information and 12001da177e4SLinus Torvalds symbolic stack backtraces. This increases the size of the kernel 12011da177e4SLinus Torvalds somewhat, as all symbols have to be loaded into the kernel image. 12021da177e4SLinus Torvalds 12031da177e4SLinus Torvaldsconfig KALLSYMS_ALL 12041da177e4SLinus Torvalds bool "Include all symbols in kallsyms" 12051da177e4SLinus Torvalds depends on DEBUG_KERNEL && KALLSYMS 12061da177e4SLinus Torvalds help 120771a83ec7SArtem Bityutskiy Normally kallsyms only contains the symbols of functions for nicer 120871a83ec7SArtem Bityutskiy OOPS messages and backtraces (i.e., symbols from the text and inittext 120971a83ec7SArtem Bityutskiy sections). This is sufficient for most cases. And only in very rare 121071a83ec7SArtem Bityutskiy cases (e.g., when a debugger is used) all symbols are required (e.g., 121171a83ec7SArtem Bityutskiy names of variables from the data sections, etc). 12121da177e4SLinus Torvalds 121371a83ec7SArtem Bityutskiy This option makes sure that all symbols are loaded into the kernel 121471a83ec7SArtem Bityutskiy image (i.e., symbols from all sections) in cost of increased kernel 121571a83ec7SArtem Bityutskiy size (depending on the kernel configuration, it may be 300KiB or 121671a83ec7SArtem Bityutskiy something like this). 12171da177e4SLinus Torvalds 121871a83ec7SArtem Bityutskiy Say N unless you really need all symbols. 1219d59745ceSMatt Mackall 1220712f47ceSGreg Kroah-Hartmanconfig HOTPLUG 12216a108a14SDavid Rientjes bool "Support for hot-pluggable devices" if EXPERT 1222712f47ceSGreg Kroah-Hartman default y 1223712f47ceSGreg Kroah-Hartman help 1224712f47ceSGreg Kroah-Hartman This option is provided for the case where no hotplug or uevent 1225712f47ceSGreg Kroah-Hartman capabilities is wanted by the kernel. You should only consider 1226712f47ceSGreg Kroah-Hartman disabling this option for embedded systems that do not use modules, a 1227712f47ceSGreg Kroah-Hartman dynamic /dev tree, or dynamic device discovery. Just say Y. 1228712f47ceSGreg Kroah-Hartman 1229d59745ceSMatt Mackallconfig PRINTK 1230d59745ceSMatt Mackall default y 12316a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 1232d59745ceSMatt Mackall help 1233d59745ceSMatt Mackall This option enables normal printk support. Removing it 1234d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1235d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1236d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1237d59745ceSMatt Mackall strongly discouraged. 1238d59745ceSMatt Mackall 1239c8538a7aSMatt Mackallconfig BUG 12406a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1241c8538a7aSMatt Mackall default y 1242c8538a7aSMatt Mackall help 1243c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1244c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1245c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1246c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1247c8538a7aSMatt Mackall Just say Y. 1248c8538a7aSMatt Mackall 1249708e9a79SMatt Mackallconfig ELF_CORE 1250708e9a79SMatt Mackall default y 12516a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1252708e9a79SMatt Mackall help 1253708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1254708e9a79SMatt Mackall 12558761f1abSRalf Baechle 1256e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 12576a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 12588761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 125915f304b6SRalf Baechle select I8253_LOCK 1260e5e1d3cbSStas Sergeev default y 1261e5e1d3cbSStas Sergeev help 1262e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1263e5e1d3cbSStas Sergeev support, saving some memory. 1264e5e1d3cbSStas Sergeev 12658761f1abSRalf Baechleconfig HAVE_PCSPKR_PLATFORM 12668761f1abSRalf Baechle bool 12678761f1abSRalf Baechle 12681da177e4SLinus Torvaldsconfig BASE_FULL 12691da177e4SLinus Torvalds default y 12706a108a14SDavid Rientjes bool "Enable full-sized data structures for core" if EXPERT 12711da177e4SLinus Torvalds help 12721da177e4SLinus Torvalds Disabling this option reduces the size of miscellaneous core 12731da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 12741da177e4SLinus Torvalds but may reduce performance. 12751da177e4SLinus Torvalds 12761da177e4SLinus Torvaldsconfig FUTEX 12776a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 12781da177e4SLinus Torvalds default y 127923f78d4aSIngo Molnar select RT_MUTEXES 12801da177e4SLinus Torvalds help 12811da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 12821da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 12831da177e4SLinus Torvalds run glibc-based applications correctly. 12841da177e4SLinus Torvalds 12851da177e4SLinus Torvaldsconfig EPOLL 12866a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 12871da177e4SLinus Torvalds default y 1288448e3ceeSAdrian Bunk select ANON_INODES 12891da177e4SLinus Torvalds help 12901da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 12911da177e4SLinus Torvalds support for epoll family of system calls. 12921da177e4SLinus Torvalds 1293fba2afaaSDavide Libenziconfig SIGNALFD 12946a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1295448e3ceeSAdrian Bunk select ANON_INODES 1296fba2afaaSDavide Libenzi default y 1297fba2afaaSDavide Libenzi help 1298fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1299fba2afaaSDavide Libenzi on a file descriptor. 1300fba2afaaSDavide Libenzi 1301fba2afaaSDavide Libenzi If unsure, say Y. 1302fba2afaaSDavide Libenzi 1303b215e283SDavide Libenziconfig TIMERFD 13046a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1305448e3ceeSAdrian Bunk select ANON_INODES 1306b215e283SDavide Libenzi default y 1307b215e283SDavide Libenzi help 1308b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1309b215e283SDavide Libenzi events on a file descriptor. 1310b215e283SDavide Libenzi 1311b215e283SDavide Libenzi If unsure, say Y. 1312b215e283SDavide Libenzi 1313e1ad7468SDavide Libenziconfig EVENTFD 13146a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1315448e3ceeSAdrian Bunk select ANON_INODES 1316e1ad7468SDavide Libenzi default y 1317e1ad7468SDavide Libenzi help 1318e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1319e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1320e1ad7468SDavide Libenzi 1321e1ad7468SDavide Libenzi If unsure, say Y. 1322e1ad7468SDavide Libenzi 13231da177e4SLinus Torvaldsconfig SHMEM 13246a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 13251da177e4SLinus Torvalds default y 13261da177e4SLinus Torvalds depends on MMU 13271da177e4SLinus Torvalds help 13281da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 13291da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 13301da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 13311da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 13321da177e4SLinus Torvalds which may be appropriate on small systems without swap. 13331da177e4SLinus Torvalds 1334ebf3f09cSThomas Petazzoniconfig AIO 13356a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1336ebf3f09cSThomas Petazzoni default y 1337ebf3f09cSThomas Petazzoni help 1338ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1339ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1340ebf3f09cSThomas Petazzoni this option saves about 7k. 1341ebf3f09cSThomas Petazzoni 13426befe5f6SRandy Dunlapconfig EMBEDDED 13436befe5f6SRandy Dunlap bool "Embedded system" 13446befe5f6SRandy Dunlap select EXPERT 13456befe5f6SRandy Dunlap help 13466befe5f6SRandy Dunlap This option should be enabled if compiling the kernel for 13476befe5f6SRandy Dunlap an embedded system so certain expert options are available 13486befe5f6SRandy Dunlap for configuration. 13496befe5f6SRandy Dunlap 1350cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 13510793a61dSThomas Gleixner bool 1352018df72dSMike Frysinger help 1353018df72dSMike Frysinger See tools/perf/design.txt for details. 13540793a61dSThomas Gleixner 1355906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 1356906010b2SPeter Zijlstra bool 1357906010b2SPeter Zijlstra help 1358906010b2SPeter Zijlstra See tools/perf/design.txt for details 1359906010b2SPeter Zijlstra 136057c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 13610793a61dSThomas Gleixner 1362cdd6c482SIngo Molnarconfig PERF_EVENTS 136357c0c15bSIngo Molnar bool "Kernel performance events and counters" 1364392d65a9SRobert Richter default y if PROFILING 1365cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 13664c59e467SIngo Molnar select ANON_INODES 1367e360adbeSPeter Zijlstra select IRQ_WORK 13680793a61dSThomas Gleixner help 136957c0c15bSIngo Molnar Enable kernel support for various performance events provided 137057c0c15bSIngo Molnar by software and hardware. 13710793a61dSThomas Gleixner 1372dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 137357c0c15bSIngo Molnar use of generic tracepoints. 137457c0c15bSIngo Molnar 137557c0c15bSIngo Molnar Most modern CPUs support performance events via performance 137657c0c15bSIngo Molnar counter registers. These registers count the number of certain 13770793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 13780793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 13790793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 13800793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 13810793a61dSThomas Gleixner used to profile the code that runs on that CPU. 13820793a61dSThomas Gleixner 138357c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 1384dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 138557c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 13860793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 13870793a61dSThomas Gleixner capabilities on top of those. 13880793a61dSThomas Gleixner 13890793a61dSThomas Gleixner Say Y if unsure. 13900793a61dSThomas Gleixner 1391906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 1392906010b2SPeter Zijlstra default n 1393906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 1394906010b2SPeter Zijlstra depends on PERF_EVENTS && DEBUG_KERNEL 1395906010b2SPeter Zijlstra select PERF_USE_VMALLOC 1396906010b2SPeter Zijlstra help 1397906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 1398906010b2SPeter Zijlstra 1399906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 1400906010b2SPeter Zijlstra that don't require it. 1401906010b2SPeter Zijlstra 1402906010b2SPeter Zijlstra Say N if unsure. 1403906010b2SPeter Zijlstra 14040793a61dSThomas Gleixnerendmenu 14050793a61dSThomas Gleixner 1406f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS 1407f8891e5eSChristoph Lameter default y 14086a108a14SDavid Rientjes bool "Enable VM event counters for /proc/vmstat" if EXPERT 1409f8891e5eSChristoph Lameter help 14102aea4fb6SPaul Jackson VM event counters are needed for event counts to be shown. 14112aea4fb6SPaul Jackson This option allows the disabling of the VM event counters 14126a108a14SDavid Rientjes on EXPERT systems. /proc/vmstat will only show page counts 14132aea4fb6SPaul Jackson if VM event counters are disabled. 1414f8891e5eSChristoph Lameter 14153d137310SThomas Petazzoniconfig PCI_QUIRKS 14163d137310SThomas Petazzoni default y 14176a108a14SDavid Rientjes bool "Enable PCI quirk workarounds" if EXPERT 141861cfc7e4SGeert Uytterhoeven depends on PCI 14193d137310SThomas Petazzoni help 14203d137310SThomas Petazzoni This enables workarounds for various PCI chipset 14213d137310SThomas Petazzoni bugs/quirks. Disable this only if your target machine is 14223d137310SThomas Petazzoni unaffected by PCI quirks. 14233d137310SThomas Petazzoni 142441ecc55bSChristoph Lameterconfig SLUB_DEBUG 142541ecc55bSChristoph Lameter default y 14266a108a14SDavid Rientjes bool "Enable SLUB debugging support" if EXPERT 1427f6acb635SChristoph Lameter depends on SLUB && SYSFS 142841ecc55bSChristoph Lameter help 142941ecc55bSChristoph Lameter SLUB has extensive debug support features. Disabling these can 143041ecc55bSChristoph Lameter result in significant savings in code size. This also disables 143141ecc55bSChristoph Lameter SLUB sysfs support. /sys/slab will not exist and there will be 143241ecc55bSChristoph Lameter no support for cache validation etc. 143341ecc55bSChristoph Lameter 1434b943c460SRandy Dunlapconfig COMPAT_BRK 1435b943c460SRandy Dunlap bool "Disable heap randomization" 1436b943c460SRandy Dunlap default y 1437b943c460SRandy Dunlap help 1438b943c460SRandy Dunlap Randomizing heap placement makes heap exploits harder, but it 1439b943c460SRandy Dunlap also breaks ancient binaries (including anything libc5 based). 1440b943c460SRandy Dunlap This option changes the bootup default to heap randomization 1441692105b8SMatt LaPlante disabled, and can be overridden at runtime by setting 1442b943c460SRandy Dunlap /proc/sys/kernel/randomize_va_space to 2. 1443b943c460SRandy Dunlap 1444b943c460SRandy Dunlap On non-ancient distros (post-2000 ones) N is usually a safe choice. 1445b943c460SRandy Dunlap 144681819f0fSChristoph Lameterchoice 144781819f0fSChristoph Lameter prompt "Choose SLAB allocator" 1448a0acd820SChristoph Lameter default SLUB 144981819f0fSChristoph Lameter help 145081819f0fSChristoph Lameter This option allows to select a slab allocator. 145181819f0fSChristoph Lameter 145281819f0fSChristoph Lameterconfig SLAB 145381819f0fSChristoph Lameter bool "SLAB" 145481819f0fSChristoph Lameter help 145581819f0fSChristoph Lameter The regular slab allocator that is established and known to work 145634013886SChristoph Lameter well in all environments. It organizes cache hot objects in 145702f56210SSimon Arlott per cpu and per node queues. 145881819f0fSChristoph Lameter 145981819f0fSChristoph Lameterconfig SLUB 146081819f0fSChristoph Lameter bool "SLUB (Unqueued Allocator)" 146181819f0fSChristoph Lameter help 146281819f0fSChristoph Lameter SLUB is a slab allocator that minimizes cache line usage 146381819f0fSChristoph Lameter instead of managing queues of cached objects (SLAB approach). 146481819f0fSChristoph Lameter Per cpu caching is realized using slabs of objects instead 146581819f0fSChristoph Lameter of queues of objects. SLUB can use memory efficiently 146602f56210SSimon Arlott and has enhanced diagnostics. SLUB is the default choice for 146702f56210SSimon Arlott a slab allocator. 146881819f0fSChristoph Lameter 146981819f0fSChristoph Lameterconfig SLOB 14706a108a14SDavid Rientjes depends on EXPERT 147181819f0fSChristoph Lameter bool "SLOB (Simple Allocator)" 147281819f0fSChristoph Lameter help 147337291458SMatt Mackall SLOB replaces the stock allocator with a drastically simpler 147437291458SMatt Mackall allocator. SLOB is generally more space efficient but 147537291458SMatt Mackall does not perform as well on large systems. 147681819f0fSChristoph Lameter 147781819f0fSChristoph Lameterendchoice 147881819f0fSChristoph Lameter 1479ea637639SJie Zhangconfig MMAP_ALLOW_UNINITIALIZED 1480ea637639SJie Zhang bool "Allow mmapped anonymous memory to be uninitialized" 14816a108a14SDavid Rientjes depends on EXPERT && !MMU 1482ea637639SJie Zhang default n 1483ea637639SJie Zhang help 1484ea637639SJie Zhang Normally, and according to the Linux spec, anonymous memory obtained 1485ea637639SJie Zhang from mmap() has it's contents cleared before it is passed to 1486ea637639SJie Zhang userspace. Enabling this config option allows you to request that 1487ea637639SJie Zhang mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus 1488ea637639SJie Zhang providing a huge performance boost. If this option is not enabled, 1489ea637639SJie Zhang then the flag will be ignored. 1490ea637639SJie Zhang 1491ea637639SJie Zhang This is taken advantage of by uClibc's malloc(), and also by 1492ea637639SJie Zhang ELF-FDPIC binfmt's brk and stack allocator. 1493ea637639SJie Zhang 1494ea637639SJie Zhang Because of the obvious security issues, this option should only be 1495ea637639SJie Zhang enabled on embedded devices where you control what is run in 1496ea637639SJie Zhang userspace. Since that isn't generally a problem on no-MMU systems, 1497ea637639SJie Zhang it is normally safe to say Y here. 1498ea637639SJie Zhang 1499ea637639SJie Zhang See Documentation/nommu-mmap.txt for more information. 1500ea637639SJie Zhang 1501125e5645SMathieu Desnoyersconfig PROFILING 1502b309a294SRobert Richter bool "Profiling support" 1503125e5645SMathieu Desnoyers help 1504125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 1505125e5645SMathieu Desnoyers by profilers such as OProfile. 1506125e5645SMathieu Desnoyers 15075f87f112SIngo Molnar# 15085f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 15095f87f112SIngo Molnar# dynamically changed for a probe function. 15105f87f112SIngo Molnar# 151197e1c18eSMathieu Desnoyersconfig TRACEPOINTS 15125f87f112SIngo Molnar bool 151397e1c18eSMathieu Desnoyers 1514fb32e03fSMathieu Desnoyerssource "arch/Kconfig" 1515fb32e03fSMathieu Desnoyers 15161da177e4SLinus Torvaldsendmenu # General setup 15171da177e4SLinus Torvalds 1518ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT 1519ee7e5516SDmitry Baryshkov bool 1520ee7e5516SDmitry Baryshkov default n 1521ee7e5516SDmitry Baryshkov 1522158a9624SLinus Torvaldsconfig SLABINFO 1523158a9624SLinus Torvalds bool 1524158a9624SLinus Torvalds depends on PROC_FS 15250f389ec6SChristoph Lameter depends on SLAB || SLUB_DEBUG 1526158a9624SLinus Torvalds default y 1527158a9624SLinus Torvalds 1528ae81f9e3SChuck Ebbertconfig RT_MUTEXES 1529ae81f9e3SChuck Ebbert boolean 1530ae81f9e3SChuck Ebbert 15311da177e4SLinus Torvaldsconfig BASE_SMALL 15321da177e4SLinus Torvalds int 15331da177e4SLinus Torvalds default 0 if BASE_FULL 15341da177e4SLinus Torvalds default 1 if !BASE_FULL 15351da177e4SLinus Torvalds 153666da5733SJan Engelhardtmenuconfig MODULES 15371da177e4SLinus Torvalds bool "Enable loadable module support" 15381da177e4SLinus Torvalds help 15391da177e4SLinus Torvalds Kernel modules are small pieces of compiled code which can 15401da177e4SLinus Torvalds be inserted in the running kernel, rather than being 15411da177e4SLinus Torvalds permanently built into the kernel. You use the "modprobe" 15421da177e4SLinus Torvalds tool to add (and sometimes remove) them. If you say Y here, 15431da177e4SLinus Torvalds many parts of the kernel can be built as modules (by 15441da177e4SLinus Torvalds answering M instead of Y where indicated): this is most 15451da177e4SLinus Torvalds useful for infrequently used options which are not required 15461da177e4SLinus Torvalds for booting. For more information, see the man pages for 15471da177e4SLinus Torvalds modprobe, lsmod, modinfo, insmod and rmmod. 15481da177e4SLinus Torvalds 15491da177e4SLinus Torvalds If you say Y here, you will need to run "make 15501da177e4SLinus Torvalds modules_install" to put the modules under /lib/modules/ 15511da177e4SLinus Torvalds where modprobe can find them (you may need to be root to do 15521da177e4SLinus Torvalds this). 15531da177e4SLinus Torvalds 15541da177e4SLinus Torvalds If unsure, say Y. 15551da177e4SLinus Torvalds 15560b0de144SRobert P. J. Dayif MODULES 15570b0de144SRobert P. J. Day 1558826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD 1559826e4506SLinus Torvalds bool "Forced module loading" 1560826e4506SLinus Torvalds default n 1561826e4506SLinus Torvalds help 156291e37a79SRusty Russell Allow loading of modules without version information (ie. modprobe 156391e37a79SRusty Russell --force). Forced module loading sets the 'F' (forced) taint flag and 156491e37a79SRusty Russell is usually a really bad idea. 1565826e4506SLinus Torvalds 15661da177e4SLinus Torvaldsconfig MODULE_UNLOAD 15671da177e4SLinus Torvalds bool "Module unloading" 15681da177e4SLinus Torvalds help 15691da177e4SLinus Torvalds Without this option you will not be able to unload any 15701da177e4SLinus Torvalds modules (note that some modules may not be unloadable 1571f7f5b675SDenys Vlasenko anyway), which makes your kernel smaller, faster 1572f7f5b675SDenys Vlasenko and simpler. If unsure, say Y. 15731da177e4SLinus Torvalds 15741da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD 15751da177e4SLinus Torvalds bool "Forced module unloading" 15761da177e4SLinus Torvalds depends on MODULE_UNLOAD && EXPERIMENTAL 15771da177e4SLinus Torvalds help 15781da177e4SLinus Torvalds This option allows you to force a module to unload, even if the 15791da177e4SLinus Torvalds kernel believes it is unsafe: the kernel will remove the module 15801da177e4SLinus Torvalds without waiting for anyone to stop using it (using the -f option to 15811da177e4SLinus Torvalds rmmod). This is mainly for kernel developers and desperate users. 15821da177e4SLinus Torvalds If unsure, say N. 15831da177e4SLinus Torvalds 15841da177e4SLinus Torvaldsconfig MODVERSIONS 15850d541643SSam Ravnborg bool "Module versioning support" 15861da177e4SLinus Torvalds help 15871da177e4SLinus Torvalds Usually, you have to use modules compiled with your kernel. 15881da177e4SLinus Torvalds Saying Y here makes it sometimes possible to use modules 15891da177e4SLinus Torvalds compiled for different kernels, by adding enough information 15901da177e4SLinus Torvalds to the modules to (hopefully) spot any changes which would 15911da177e4SLinus Torvalds make them incompatible with the kernel you are running. If 15921da177e4SLinus Torvalds unsure, say N. 15931da177e4SLinus Torvalds 15941da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL 15951da177e4SLinus Torvalds bool "Source checksum for all modules" 15961da177e4SLinus Torvalds help 15971da177e4SLinus Torvalds Modules which contain a MODULE_VERSION get an extra "srcversion" 15981da177e4SLinus Torvalds field inserted into their modinfo section, which contains a 15991da177e4SLinus Torvalds sum of the source files which made it. This helps maintainers 16001da177e4SLinus Torvalds see exactly which source was used to build a module (since 16011da177e4SLinus Torvalds others sometimes change the module source without updating 16021da177e4SLinus Torvalds the version). With this option, such a "srcversion" field 16031da177e4SLinus Torvalds will be created for all modules. If unsure, say N. 16041da177e4SLinus Torvalds 16050b0de144SRobert P. J. Dayendif # MODULES 16060b0de144SRobert P. J. Day 160798a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 160898a79d6aSRusty Russell bool 160998a79d6aSRusty Russell help 16105f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 16115f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 161298a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 161398a79d6aSRusty Russell it was better to provide this option than to break all the archs 1614692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 161598a79d6aSRusty Russell 16161da177e4SLinus Torvaldsconfig STOP_MACHINE 16171da177e4SLinus Torvalds bool 16181da177e4SLinus Torvalds default y 16191da177e4SLinus Torvalds depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 16201da177e4SLinus Torvalds help 16211da177e4SLinus Torvalds Need stop_machine() primitive. 16223a65dfe8SJens Axboe 16233a65dfe8SJens Axboesource "block/Kconfig" 1624e98c3202SAvi Kivity 1625e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 1626e98c3202SAvi Kivity bool 1627e260be67SPaul E. McKenney 162816295becSSteffen Klassertconfig PADATA 162916295becSSteffen Klassert depends on SMP 163016295becSSteffen Klassert bool 163116295becSSteffen Klassert 16326beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 1633