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 IRQ_WORK 24e360adbeSPeter Zijlstra bool 25e360adbeSPeter Zijlstra 261dbdc6f1SDavid Daneyconfig BUILDTIME_EXTABLE_SORT 271dbdc6f1SDavid Daney bool 281dbdc6f1SDavid Daney 29ff0cfc66SAl Boldimenu "General setup" 301da177e4SLinus Torvalds 311da177e4SLinus Torvaldsconfig EXPERIMENTAL 321da177e4SLinus Torvalds bool "Prompt for development and/or incomplete code/drivers" 331da177e4SLinus Torvalds ---help--- 341da177e4SLinus Torvalds Some of the various things that Linux supports (such as network 351da177e4SLinus Torvalds drivers, file systems, network protocols, etc.) can be in a state 361da177e4SLinus Torvalds of development where the functionality, stability, or the level of 371da177e4SLinus Torvalds testing is not yet high enough for general use. This is usually 381da177e4SLinus Torvalds known as the "alpha-test" phase among developers. If a feature is 391da177e4SLinus Torvalds currently in alpha-test, then the developers usually discourage 401da177e4SLinus Torvalds uninformed widespread use of this feature by the general public to 411da177e4SLinus Torvalds avoid "Why doesn't this work?" type mail messages. However, active 421da177e4SLinus Torvalds testing and use of these systems is welcomed. Just be aware that it 431da177e4SLinus Torvalds may not meet the normal level of reliability or it may fail to work 441da177e4SLinus Torvalds in some special cases. Detailed bug reports from people familiar 451da177e4SLinus Torvalds with the kernel internals are usually welcomed by the developers 461da177e4SLinus Torvalds (before submitting bug reports, please read the documents 471da177e4SLinus Torvalds <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 481da177e4SLinus Torvalds <file:Documentation/BUG-HUNTING>, and 491da177e4SLinus Torvalds <file:Documentation/oops-tracing.txt> in the kernel source). 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds This option will also make obsoleted drivers available. These are 521da177e4SLinus Torvalds drivers that have been replaced by something else, and/or are 531da177e4SLinus Torvalds scheduled to be removed in a future kernel release. 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds Unless you intend to help test and develop a feature or driver that 561da177e4SLinus Torvalds falls into this category, or you have a situation that requires 571da177e4SLinus Torvalds using these features, you should probably say N here, which will 581da177e4SLinus Torvalds cause the configurator to present you with fewer choices. If 591da177e4SLinus Torvalds you say Y here, you will be offered the choice of using features or 601da177e4SLinus Torvalds drivers that are currently considered to be in the alpha-test phase. 611da177e4SLinus Torvalds 621da177e4SLinus Torvaldsconfig BROKEN 631da177e4SLinus Torvalds bool 641da177e4SLinus Torvalds 651da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 661da177e4SLinus Torvalds bool 671da177e4SLinus Torvalds depends on BROKEN || !SMP 681da177e4SLinus Torvalds default y 691da177e4SLinus Torvalds 701da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 711da177e4SLinus Torvalds int 72dd673bcaSAdrian Bunk default 32 if !UML 73dd673bcaSAdrian Bunk default 128 if UML 741da177e4SLinus Torvalds help 7534ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 7634ad92c2SRandy Dunlap variables passed to init from the kernel command line. 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds 7984336466SRoland McGrathconfig CROSS_COMPILE 8084336466SRoland McGrath string "Cross-compiler tool prefix" 8184336466SRoland McGrath help 8284336466SRoland McGrath Same as running 'make CROSS_COMPILE=prefix-' but stored for 8384336466SRoland McGrath default make runs in this kernel build directory. You don't 8484336466SRoland McGrath need to set this unless you want the configured kernel build 8584336466SRoland McGrath directory to select the cross-compiler automatically. 8684336466SRoland McGrath 871da177e4SLinus Torvaldsconfig LOCALVERSION 881da177e4SLinus Torvalds string "Local version - append to kernel release" 891da177e4SLinus Torvalds help 901da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 911da177e4SLinus Torvalds This will show up when you type uname, for example. 921da177e4SLinus Torvalds The string you set here will be appended after the contents of 931da177e4SLinus Torvalds any files with a filename matching localversion* in your 941da177e4SLinus Torvalds object and source tree, in that order. Your total string can 951da177e4SLinus Torvalds be a maximum of 64 characters. 961da177e4SLinus Torvalds 97aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 98aaebf433SRyan Anderson bool "Automatically append version information to the version string" 99aaebf433SRyan Anderson default y 100aaebf433SRyan Anderson help 101aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 1026e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 1036e5a5420SRobert P. J. Day top of tree revision. 104aaebf433SRyan Anderson 105aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 1066e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 107aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 1086e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 109aaebf433SRyan Anderson 1106e5a5420SRobert P. J. Day (The actual string used here is the first eight characters produced 1116e5a5420SRobert P. J. Day by running the command: 1126e5a5420SRobert P. J. Day 1136e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 1146e5a5420SRobert P. J. Day 1156e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 116aaebf433SRyan Anderson 1172e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 1182e9f3bddSH. Peter Anvin bool 1192e9f3bddSH. Peter Anvin 1202e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 1212e9f3bddSH. Peter Anvin bool 1222e9f3bddSH. Peter Anvin 1232e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 1242e9f3bddSH. Peter Anvin bool 1252e9f3bddSH. Peter Anvin 1263ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 1273ebe1243SLasse Collin bool 1283ebe1243SLasse Collin 1297dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 1307dd65febSAlbin Tonnerre bool 1317dd65febSAlbin Tonnerre 13230d65dbfSAlain Knaffchoice 13330d65dbfSAlain Knaff prompt "Kernel compression mode" 13430d65dbfSAlain Knaff default KERNEL_GZIP 1353ebe1243SLasse Collin depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO 13630d65dbfSAlain Knaff help 13730d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 13830d65dbfSAlain Knaff Several compression algorithms are available, which differ 13930d65dbfSAlain Knaff in efficiency, compression and decompression speed. 14030d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 14130d65dbfSAlain Knaff Decompression speed is relevant at each boot. 14230d65dbfSAlain Knaff 14330d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 14430d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 14530d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 14630d65dbfSAlain Knaff supplied by Christian Ludwig) 14730d65dbfSAlain Knaff 14830d65dbfSAlain Knaff High compression options are mostly useful for users, who 14930d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 15030d65dbfSAlain Knaff size matters less. 15130d65dbfSAlain Knaff 15230d65dbfSAlain Knaff If in doubt, select 'gzip' 15330d65dbfSAlain Knaff 15430d65dbfSAlain Knaffconfig KERNEL_GZIP 15530d65dbfSAlain Knaff bool "Gzip" 1562e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 15730d65dbfSAlain Knaff help 1587dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 1597dd65febSAlbin Tonnerre between compression ratio and decompression speed. 16030d65dbfSAlain Knaff 16130d65dbfSAlain Knaffconfig KERNEL_BZIP2 16230d65dbfSAlain Knaff bool "Bzip2" 1632e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 16430d65dbfSAlain Knaff help 16530d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 1660a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 1672e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 1682e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 1692e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 17030d65dbfSAlain Knaff 17130d65dbfSAlain Knaffconfig KERNEL_LZMA 17230d65dbfSAlain Knaff bool "LZMA" 1732e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 17430d65dbfSAlain Knaff help 1750a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 1760a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 1770a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 17830d65dbfSAlain Knaff 1793ebe1243SLasse Collinconfig KERNEL_XZ 1803ebe1243SLasse Collin bool "XZ" 1813ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 1823ebe1243SLasse Collin help 1833ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 1843ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 1853ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 1863ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 1873ebe1243SLasse Collin filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ 1883ebe1243SLasse Collin will create a few percent smaller kernel than plain LZMA. 1893ebe1243SLasse Collin 1903ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 1913ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 1923ebe1243SLasse Collin and LZO. Compression is slow. 1933ebe1243SLasse Collin 1947dd65febSAlbin Tonnerreconfig KERNEL_LZO 1957dd65febSAlbin Tonnerre bool "LZO" 1967dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 1977dd65febSAlbin Tonnerre help 1980a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 199681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 2007dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 2017dd65febSAlbin Tonnerre 20230d65dbfSAlain Knaffendchoice 20330d65dbfSAlain Knaff 204bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 205bd5dc17bSJosh Triplett string "Default hostname" 206bd5dc17bSJosh Triplett default "(none)" 207bd5dc17bSJosh Triplett help 208bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 209bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 210bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 211bd5dc17bSJosh Triplett system more usable with less configuration. 212bd5dc17bSJosh Triplett 2131da177e4SLinus Torvaldsconfig SWAP 2141da177e4SLinus Torvalds bool "Support for paging of anonymous memory (swap)" 2159361401eSDavid Howells depends on MMU && BLOCK 2161da177e4SLinus Torvalds default y 2171da177e4SLinus Torvalds help 2181da177e4SLinus Torvalds This option allows you to choose whether you want to have support 2191da177e4SLinus Torvalds for so called swap devices or swap files in your kernel that are 2201da177e4SLinus Torvalds used to provide more virtual memory than the actual RAM present 2211da177e4SLinus Torvalds in your computer. If unsure say Y. 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvaldsconfig SYSVIPC 2241da177e4SLinus Torvalds bool "System V IPC" 2251da177e4SLinus Torvalds ---help--- 2261da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 2271da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 2281da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 2291da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 2301da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 2311da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 2321da177e4SLinus Torvalds you'll need to say Y here. 2331da177e4SLinus Torvalds 2341da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 2351da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 2361da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 2371da177e4SLinus Torvalds 238a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 239a5494dcdSEric W. Biederman bool 240a5494dcdSEric W. Biederman depends on SYSVIPC 241a5494dcdSEric W. Biederman depends on SYSCTL 242a5494dcdSEric W. Biederman default y 243a5494dcdSEric W. Biederman 2441da177e4SLinus Torvaldsconfig POSIX_MQUEUE 2451da177e4SLinus Torvalds bool "POSIX Message Queues" 2461da177e4SLinus Torvalds depends on NET && EXPERIMENTAL 2471da177e4SLinus Torvalds ---help--- 2481da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 2491da177e4SLinus Torvalds queues every message has a priority which decides about succession 2501da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 2511da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 252b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 2531da177e4SLinus Torvalds 2541da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 2551da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 2561da177e4SLinus Torvalds operations on message queues. 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds If unsure, say Y. 2591da177e4SLinus Torvalds 260bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 261bdc8e5f8SSerge E. Hallyn bool 262bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 263bdc8e5f8SSerge E. Hallyn depends on SYSCTL 264bdc8e5f8SSerge E. Hallyn default y 265bdc8e5f8SSerge E. Hallyn 266990d6c2dSAneesh Kumar K.Vconfig FHANDLE 267990d6c2dSAneesh Kumar K.V bool "open by fhandle syscalls" 268990d6c2dSAneesh Kumar K.V select EXPORTFS 269990d6c2dSAneesh Kumar K.V help 270990d6c2dSAneesh Kumar K.V If you say Y here, a user level program will be able to map 271990d6c2dSAneesh Kumar K.V file names to handle and then later use the handle for 272990d6c2dSAneesh Kumar K.V different file system operations. This is useful in implementing 273990d6c2dSAneesh Kumar K.V userspace file servers, which now track files using handles instead 274990d6c2dSAneesh Kumar K.V of names. The handle would remain the same even if file names 275990d6c2dSAneesh Kumar K.V get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 276990d6c2dSAneesh Kumar K.V syscalls. 277990d6c2dSAneesh Kumar K.V 2781da177e4SLinus Torvaldsconfig AUDIT 2791da177e4SLinus Torvalds bool "Auditing support" 280804a6a49SChris Wright depends on NET 2811da177e4SLinus Torvalds help 2821da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 2831da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 2841da177e4SLinus Torvalds logging of avc messages output). Does not do system-call 2851da177e4SLinus Torvalds auditing without CONFIG_AUDITSYSCALL. 2861da177e4SLinus Torvalds 2871da177e4SLinus Torvaldsconfig AUDITSYSCALL 2881da177e4SLinus Torvalds bool "Enable system-call auditing support" 2898f827a14SWill Deacon depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) 2901da177e4SLinus Torvalds default y if SECURITY_SELINUX 2911da177e4SLinus Torvalds help 2921da177e4SLinus Torvalds Enable low-overhead system-call auditing infrastructure that 2931da177e4SLinus Torvalds can be used independently or with another kernel subsystem, 29467640b60SEric Paris such as SELinux. 2951da177e4SLinus Torvalds 296939a67fcSEric Parisconfig AUDIT_WATCH 297939a67fcSEric Paris def_bool y 298939a67fcSEric Paris depends on AUDITSYSCALL 299939a67fcSEric Paris select FSNOTIFY 3001da177e4SLinus Torvalds 30174c3cbe3SAl Viroconfig AUDIT_TREE 30274c3cbe3SAl Viro def_bool y 30363c882a0SEric Paris depends on AUDITSYSCALL 30428a3a7ebSEric Paris select FSNOTIFY 30574c3cbe3SAl Viro 306633b4545SEric Parisconfig AUDIT_LOGINUID_IMMUTABLE 307633b4545SEric Paris bool "Make audit loginuid immutable" 308633b4545SEric Paris depends on AUDIT 309633b4545SEric Paris help 310f429ee3bSLinus Torvalds The config option toggles if a task setting its loginuid requires 311633b4545SEric Paris CAP_SYS_AUDITCONTROL or if that task should require no special permissions 312633b4545SEric Paris but should instead only allow setting its loginuid if it was never 313633b4545SEric Paris previously set. On systems which use systemd or a similar central 314633b4545SEric Paris process to restart login services this should be set to true. On older 315633b4545SEric Paris systems in which an admin would typically have to directly stop and 316633b4545SEric Paris start processes this should be set to false. Setting this to true allows 317633b4545SEric Paris one to drop potentially dangerous capabilites from the login tasks, 318633b4545SEric Paris but may not be backwards compatible with older init systems. 319633b4545SEric Paris 320d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 321764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 322d9817ebeSThomas Gleixner 323391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 324391dc69cSFrederic Weisbecker 325fdf9c356SFrederic Weisbeckerchoice 326fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 327fdf9c356SFrederic Weisbecker default TICK_CPU_ACCOUNTING if !PPC64 328fdf9c356SFrederic Weisbecker default VIRT_CPU_ACCOUNTING if PPC64 329fdf9c356SFrederic Weisbecker 330fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 331fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 332fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 333fdf9c356SFrederic Weisbecker depends on !S390 334fdf9c356SFrederic Weisbecker help 335fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 336fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 337fdf9c356SFrederic Weisbecker granularity. 338fdf9c356SFrederic Weisbecker 339fdf9c356SFrederic Weisbecker If unsure, say Y. 340fdf9c356SFrederic Weisbecker 341391dc69cSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 342391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 343391dc69cSFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING 344391dc69cSFrederic Weisbecker help 345391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 346391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 347391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 348391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 349391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 350391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 351391dc69cSFrederic Weisbecker systems. 352391dc69cSFrederic Weisbecker 353fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 354fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 355fdf9c356SFrederic Weisbecker depends on HAVE_IRQ_TIME_ACCOUNTING 356fdf9c356SFrederic Weisbecker help 357fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 358fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 359fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 360fdf9c356SFrederic Weisbecker small performance impact. 361fdf9c356SFrederic Weisbecker 362fdf9c356SFrederic Weisbecker If in doubt, say N here. 363fdf9c356SFrederic Weisbecker 364fdf9c356SFrederic Weisbeckerendchoice 365fdf9c356SFrederic Weisbecker 366391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 367391dc69cSFrederic Weisbecker bool "BSD Process Accounting" 368391dc69cSFrederic Weisbecker help 369391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 370391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 371391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 372391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 373391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 374391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 375391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 376391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 377391dc69cSFrederic Weisbecker information. This is generally a good idea, so say Y. 378391dc69cSFrederic Weisbecker 379391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 380391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 381391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 382391dc69cSFrederic Weisbecker default n 383391dc69cSFrederic Weisbecker help 384391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 385391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 386391dc69cSFrederic Weisbecker process and it's parent. Note that this file format is incompatible 387391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 388391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 389391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 390391dc69cSFrederic Weisbecker 391391dc69cSFrederic Weisbeckerconfig TASKSTATS 392391dc69cSFrederic Weisbecker bool "Export task/process statistics through netlink (EXPERIMENTAL)" 393391dc69cSFrederic Weisbecker depends on NET 394391dc69cSFrederic Weisbecker default n 395391dc69cSFrederic Weisbecker help 396391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 397391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 398391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 399391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 400391dc69cSFrederic Weisbecker space on task exit. 401391dc69cSFrederic Weisbecker 402391dc69cSFrederic Weisbecker Say N if unsure. 403391dc69cSFrederic Weisbecker 404391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 405391dc69cSFrederic Weisbecker bool "Enable per-task delay accounting (EXPERIMENTAL)" 406391dc69cSFrederic Weisbecker depends on TASKSTATS 407391dc69cSFrederic Weisbecker help 408391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 409391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 410391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 411391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 412391dc69cSFrederic Weisbecker 413391dc69cSFrederic Weisbecker Say N if unsure. 414391dc69cSFrederic Weisbecker 415391dc69cSFrederic Weisbeckerconfig TASK_XACCT 416391dc69cSFrederic Weisbecker bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 417391dc69cSFrederic Weisbecker depends on TASKSTATS 418391dc69cSFrederic Weisbecker help 419391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 420391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 421391dc69cSFrederic Weisbecker 422391dc69cSFrederic Weisbecker Say N if unsure. 423391dc69cSFrederic Weisbecker 424391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 425391dc69cSFrederic Weisbecker bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 426391dc69cSFrederic Weisbecker depends on TASK_XACCT 427391dc69cSFrederic Weisbecker help 428391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 429391dc69cSFrederic Weisbecker task has caused. 430391dc69cSFrederic Weisbecker 431391dc69cSFrederic Weisbecker Say N if unsure. 432391dc69cSFrederic Weisbecker 433391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 434391dc69cSFrederic Weisbecker 435c903ff83SMike Travismenu "RCU Subsystem" 436c903ff83SMike Travis 437c903ff83SMike Travischoice 438c903ff83SMike Travis prompt "RCU Implementation" 43931c9a24eSPaul E. McKenney default TREE_RCU 440c903ff83SMike Travis 441c903ff83SMike Travisconfig TREE_RCU 442c903ff83SMike Travis bool "Tree-based hierarchical RCU" 443687d7a96SPaul E. McKenney depends on !PREEMPT && SMP 444c903ff83SMike Travis help 445c903ff83SMike Travis This option selects the RCU implementation that is 446c903ff83SMike Travis designed for very large SMP system with hundreds or 447c17ef453SPaul E. McKenney thousands of CPUs. It also scales down nicely to 448c17ef453SPaul E. McKenney smaller systems. 449c903ff83SMike Travis 450f41d911fSPaul E. McKenneyconfig TREE_PREEMPT_RCU 451a57eb940SPaul E. McKenney bool "Preemptible tree-based hierarchical RCU" 4528008e129SPaul E. McKenney depends on PREEMPT && SMP 453f41d911fSPaul E. McKenney help 454f41d911fSPaul E. McKenney This option selects the RCU implementation that is 455f41d911fSPaul E. McKenney designed for very large SMP systems with hundreds or 456f41d911fSPaul E. McKenney thousands of CPUs, but for which real-time response 457bbe3eae8SPaul E. McKenney is also required. It also scales down nicely to 458bbe3eae8SPaul E. McKenney smaller systems. 459f41d911fSPaul E. McKenney 4609b1d82faSPaul E. McKenneyconfig TINY_RCU 4619b1d82faSPaul E. McKenney bool "UP-only small-memory-footprint RCU" 4628008e129SPaul E. McKenney depends on !PREEMPT && !SMP 4639b1d82faSPaul E. McKenney help 4649b1d82faSPaul E. McKenney This option selects the RCU implementation that is 4659b1d82faSPaul E. McKenney designed for UP systems from which real-time response 4669b1d82faSPaul E. McKenney is not required. This option greatly reduces the 4679b1d82faSPaul E. McKenney memory footprint of RCU. 4689b1d82faSPaul E. McKenney 469a57eb940SPaul E. McKenneyconfig TINY_PREEMPT_RCU 470a57eb940SPaul E. McKenney bool "Preemptible UP-only small-memory-footprint RCU" 4718008e129SPaul E. McKenney depends on PREEMPT && !SMP 472a57eb940SPaul E. McKenney help 473a57eb940SPaul E. McKenney This option selects the RCU implementation that is designed 474a57eb940SPaul E. McKenney for real-time UP systems. This option greatly reduces the 475a57eb940SPaul E. McKenney memory footprint of RCU. 476a57eb940SPaul E. McKenney 477c903ff83SMike Travisendchoice 478c903ff83SMike Travis 479a57eb940SPaul E. McKenneyconfig PREEMPT_RCU 480a57eb940SPaul E. McKenney def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) 481a57eb940SPaul E. McKenney help 482a57eb940SPaul E. McKenney This option enables preemptible-RCU code that is common between 483a57eb940SPaul E. McKenney the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. 484a57eb940SPaul E. McKenney 4852b1d5024SFrederic Weisbeckerconfig RCU_USER_QS 4862b1d5024SFrederic Weisbecker bool "Consider userspace as in RCU extended quiescent state" 4872b1d5024SFrederic Weisbecker depends on HAVE_RCU_USER_QS && SMP 4882b1d5024SFrederic Weisbecker help 4892b1d5024SFrederic Weisbecker This option sets hooks on kernel / userspace boundaries and 4902b1d5024SFrederic Weisbecker puts RCU in extended quiescent state when the CPU runs in 4912b1d5024SFrederic Weisbecker userspace. It means that when a CPU runs in userspace, it is 4922b1d5024SFrederic Weisbecker excluded from the global RCU state machine and thus doesn't 4932b1d5024SFrederic Weisbecker to keep the timer tick on for RCU. 4942b1d5024SFrederic Weisbecker 495d677124bSFrederic Weisbecker Unless you want to hack and help the development of the full 496d677124bSFrederic Weisbecker tickless feature, you shouldn't enable this option. It adds 497d677124bSFrederic Weisbecker unnecessary overhead. 498d677124bSFrederic Weisbecker 499d677124bSFrederic Weisbecker If unsure say N 500d677124bSFrederic Weisbecker 5011fd2b442SFrederic Weisbeckerconfig RCU_USER_QS_FORCE 5021fd2b442SFrederic Weisbecker bool "Force userspace extended QS by default" 5031fd2b442SFrederic Weisbecker depends on RCU_USER_QS 5041fd2b442SFrederic Weisbecker help 5051fd2b442SFrederic Weisbecker Set the hooks in user/kernel boundaries by default in order to 5061fd2b442SFrederic Weisbecker test this feature that treats userspace as an extended quiescent 5071fd2b442SFrederic Weisbecker state until we have a real user like a full adaptive nohz option. 5081fd2b442SFrederic Weisbecker 509d677124bSFrederic Weisbecker Unless you want to hack and help the development of the full 510d677124bSFrederic Weisbecker tickless feature, you shouldn't enable this option. It adds 511d677124bSFrederic Weisbecker unnecessary overhead. 512d677124bSFrederic Weisbecker 513d677124bSFrederic Weisbecker If unsure say N 514d677124bSFrederic Weisbecker 515c903ff83SMike Travisconfig RCU_FANOUT 516c903ff83SMike Travis int "Tree-based hierarchical RCU fanout value" 517c903ff83SMike Travis range 2 64 if 64BIT 518c903ff83SMike Travis range 2 32 if !64BIT 519f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 520c903ff83SMike Travis default 64 if 64BIT 521c903ff83SMike Travis default 32 if !64BIT 522c903ff83SMike Travis help 523c903ff83SMike Travis This option controls the fanout of hierarchical implementations 524c903ff83SMike Travis of RCU, allowing RCU to work efficiently on machines with 5254d87ffadSPaul E. McKenney large numbers of CPUs. This value must be at least the fourth 5264d87ffadSPaul E. McKenney root of NR_CPUS, which allows NR_CPUS to be insanely large. 5274d87ffadSPaul E. McKenney The default value of RCU_FANOUT should be used for production 5284d87ffadSPaul E. McKenney systems, but if you are stress-testing the RCU implementation 5294d87ffadSPaul E. McKenney itself, small RCU_FANOUT values allow you to test large-system 5304d87ffadSPaul E. McKenney code paths on small(er) systems. 531c903ff83SMike Travis 532c903ff83SMike Travis Select a specific number if testing RCU itself. 533c903ff83SMike Travis Take the default if unsure. 534c903ff83SMike Travis 5358932a63dSPaul E. McKenneyconfig RCU_FANOUT_LEAF 5368932a63dSPaul E. McKenney int "Tree-based hierarchical RCU leaf-level fanout value" 5378932a63dSPaul E. McKenney range 2 RCU_FANOUT if 64BIT 5388932a63dSPaul E. McKenney range 2 RCU_FANOUT if !64BIT 5398932a63dSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 5408932a63dSPaul E. McKenney default 16 5418932a63dSPaul E. McKenney help 5428932a63dSPaul E. McKenney This option controls the leaf-level fanout of hierarchical 5438932a63dSPaul E. McKenney implementations of RCU, and allows trading off cache misses 5448932a63dSPaul E. McKenney against lock contention. Systems that synchronize their 5458932a63dSPaul E. McKenney scheduling-clock interrupts for energy-efficiency reasons will 5468932a63dSPaul E. McKenney want the default because the smaller leaf-level fanout keeps 5478932a63dSPaul E. McKenney lock contention levels acceptably low. Very large systems 5488932a63dSPaul E. McKenney (hundreds or thousands of CPUs) will instead want to set this 5498932a63dSPaul E. McKenney value to the maximum value possible in order to reduce the 5508932a63dSPaul E. McKenney number of cache misses incurred during RCU's grace-period 5518932a63dSPaul E. McKenney initialization. These systems tend to run CPU-bound, and thus 5528932a63dSPaul E. McKenney are not helped by synchronized interrupts, and thus tend to 5538932a63dSPaul E. McKenney skew them, which reduces lock contention enough that large 5548932a63dSPaul E. McKenney leaf-level fanouts work well. 5558932a63dSPaul E. McKenney 5568932a63dSPaul E. McKenney Select a specific number if testing RCU itself. 5578932a63dSPaul E. McKenney 5588932a63dSPaul E. McKenney Select the maximum permissible value for large systems. 5598932a63dSPaul E. McKenney 5608932a63dSPaul E. McKenney Take the default if unsure. 5618932a63dSPaul E. McKenney 562c903ff83SMike Travisconfig RCU_FANOUT_EXACT 563c903ff83SMike Travis bool "Disable tree-based hierarchical RCU auto-balancing" 564f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 565c903ff83SMike Travis default n 566c903ff83SMike Travis help 567c903ff83SMike Travis This option forces use of the exact RCU_FANOUT value specified, 568c903ff83SMike Travis regardless of imbalances in the hierarchy. This is useful for 569c903ff83SMike Travis testing RCU itself, and might one day be useful on systems with 570c903ff83SMike Travis strong NUMA behavior. 571c903ff83SMike Travis 572c903ff83SMike Travis Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 573c903ff83SMike Travis 574c903ff83SMike Travis Say N if unsure. 575c903ff83SMike Travis 5768bd93a2cSPaul E. McKenneyconfig RCU_FAST_NO_HZ 5778bd93a2cSPaul E. McKenney bool "Accelerate last non-dyntick-idle CPU's grace periods" 578b807fbffSPaul E. McKenney depends on NO_HZ && SMP 5798bd93a2cSPaul E. McKenney default n 5808bd93a2cSPaul E. McKenney help 5818bd93a2cSPaul E. McKenney This option causes RCU to attempt to accelerate grace periods 582b807fbffSPaul E. McKenney in order to allow CPUs to enter dynticks-idle state more 583b807fbffSPaul E. McKenney quickly. On the other hand, this option increases the overhead 584b807fbffSPaul E. McKenney of the dynticks-idle checking, particularly on systems with 585b807fbffSPaul E. McKenney large numbers of CPUs. 5868bd93a2cSPaul E. McKenney 5878bd93a2cSPaul E. McKenney Say Y if energy efficiency is critically important, particularly 5888bd93a2cSPaul E. McKenney if you have relatively few CPUs. 5898bd93a2cSPaul E. McKenney 5908bd93a2cSPaul E. McKenney Say N if you are unsure. 5918bd93a2cSPaul E. McKenney 592c903ff83SMike Travisconfig TREE_RCU_TRACE 593f41d911fSPaul E. McKenney def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) 594c903ff83SMike Travis select DEBUG_FS 595c903ff83SMike Travis help 596f41d911fSPaul E. McKenney This option provides tracing for the TREE_RCU and 597f41d911fSPaul E. McKenney TREE_PREEMPT_RCU implementations, permitting Makefile to 598f41d911fSPaul E. McKenney trivially select kernel/rcutree_trace.c. 599c903ff83SMike Travis 60024278d14SPaul E. McKenneyconfig RCU_BOOST 60124278d14SPaul E. McKenney bool "Enable RCU priority boosting" 60227f4d280SPaul E. McKenney depends on RT_MUTEXES && PREEMPT_RCU 60324278d14SPaul E. McKenney default n 60424278d14SPaul E. McKenney help 60524278d14SPaul E. McKenney This option boosts the priority of preempted RCU readers that 60624278d14SPaul E. McKenney block the current preemptible RCU grace period for too long. 60724278d14SPaul E. McKenney This option also prevents heavy loads from blocking RCU 60824278d14SPaul E. McKenney callback invocation for all flavors of RCU. 60924278d14SPaul E. McKenney 61024278d14SPaul E. McKenney Say Y here if you are working with real-time apps or heavy loads 61124278d14SPaul E. McKenney Say N here if you are unsure. 61224278d14SPaul E. McKenney 61324278d14SPaul E. McKenneyconfig RCU_BOOST_PRIO 61424278d14SPaul E. McKenney int "Real-time priority to boost RCU readers to" 61524278d14SPaul E. McKenney range 1 99 61624278d14SPaul E. McKenney depends on RCU_BOOST 61724278d14SPaul E. McKenney default 1 61824278d14SPaul E. McKenney help 619c9336643SPaul E. McKenney This option specifies the real-time priority to which long-term 620c9336643SPaul E. McKenney preempted RCU readers are to be boosted. If you are working 621c9336643SPaul E. McKenney with a real-time application that has one or more CPU-bound 622c9336643SPaul E. McKenney threads running at a real-time priority level, you should set 623c9336643SPaul E. McKenney RCU_BOOST_PRIO to a priority higher then the highest-priority 624c9336643SPaul E. McKenney real-time CPU-bound thread. The default RCU_BOOST_PRIO value 625c9336643SPaul E. McKenney of 1 is appropriate in the common case, which is real-time 626c9336643SPaul E. McKenney applications that do not have any CPU-bound threads. 627c9336643SPaul E. McKenney 628c9336643SPaul E. McKenney Some real-time applications might not have a single real-time 629c9336643SPaul E. McKenney thread that saturates a given CPU, but instead might have 630c9336643SPaul E. McKenney multiple real-time threads that, taken together, fully utilize 631c9336643SPaul E. McKenney that CPU. In this case, you should set RCU_BOOST_PRIO to 632c9336643SPaul E. McKenney a priority higher than the lowest-priority thread that is 633c9336643SPaul E. McKenney conspiring to prevent the CPU from running any non-real-time 634c9336643SPaul E. McKenney tasks. For example, if one thread at priority 10 and another 635c9336643SPaul E. McKenney thread at priority 5 are between themselves fully consuming 636c9336643SPaul E. McKenney the CPU time on a given CPU, then RCU_BOOST_PRIO should be 637c9336643SPaul E. McKenney set to priority 6 or higher. 63824278d14SPaul E. McKenney 63924278d14SPaul E. McKenney Specify the real-time priority, or take the default if unsure. 64024278d14SPaul E. McKenney 64124278d14SPaul E. McKenneyconfig RCU_BOOST_DELAY 64224278d14SPaul E. McKenney int "Milliseconds to delay boosting after RCU grace-period start" 64324278d14SPaul E. McKenney range 0 3000 64424278d14SPaul E. McKenney depends on RCU_BOOST 64524278d14SPaul E. McKenney default 500 64624278d14SPaul E. McKenney help 64724278d14SPaul E. McKenney This option specifies the time to wait after the beginning of 64824278d14SPaul E. McKenney a given grace period before priority-boosting preempted RCU 64924278d14SPaul E. McKenney readers blocking that grace period. Note that any RCU reader 65024278d14SPaul E. McKenney blocking an expedited RCU grace period is boosted immediately. 65124278d14SPaul E. McKenney 65224278d14SPaul E. McKenney Accept the default if unsure. 65324278d14SPaul E. McKenney 654c903ff83SMike Travisendmenu # "RCU Subsystem" 655c903ff83SMike Travis 6561da177e4SLinus Torvaldsconfig IKCONFIG 657f2443ab6SRoss Biro tristate "Kernel .config support" 6581da177e4SLinus Torvalds ---help--- 6591da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 6601da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 6611da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 6621da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 6631da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 6641da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 6651da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 6661da177e4SLinus Torvalds /proc/config.gz if enabled (below). 6671da177e4SLinus Torvalds 6681da177e4SLinus Torvaldsconfig IKCONFIG_PROC 6691da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 6701da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 6711da177e4SLinus Torvalds ---help--- 6721da177e4SLinus Torvalds This option enables access to the kernel configuration file 6731da177e4SLinus Torvalds through /proc/config.gz. 6741da177e4SLinus Torvalds 675794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 676794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 677794543a2SAlistair John Strachan range 12 21 678f17a32e9SAdrian Bunk default 17 679794543a2SAlistair John Strachan help 680794543a2SAlistair John Strachan Select kernel log buffer size as a power of 2. 681f17a32e9SAdrian Bunk Examples: 682f17a32e9SAdrian Bunk 17 => 128 KB 683f17a32e9SAdrian Bunk 16 => 64 KB 684f17a32e9SAdrian Bunk 15 => 32 KB 685f17a32e9SAdrian Bunk 14 => 16 KB 686794543a2SAlistair John Strachan 13 => 8 KB 687794543a2SAlistair John Strachan 12 => 4 KB 688794543a2SAlistair John Strachan 6895cdc38f9SKAMEZAWA Hiroyuki# 6905cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 6915cdc38f9SKAMEZAWA Hiroyuki# 6925cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 6935cdc38f9SKAMEZAWA Hiroyuki bool 6945cdc38f9SKAMEZAWA Hiroyuki 69523964d2dSLi Zefanmenuconfig CGROUPS 69623964d2dSLi Zefan boolean "Control Group support" 6970dea1168SKirill A. Shutemov depends on EVENTFD 698ddbcc7e8SPaul Menage help 69923964d2dSLi Zefan This option adds support for grouping sets of processes together, for 7005cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 7015cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 7025cdc38f9SKAMEZAWA Hiroyuki See 7035cdc38f9SKAMEZAWA Hiroyuki - Documentation/scheduler/sched-design-CFS.txt (CFS) 70445ce80fbSLi Zefan - Documentation/cgroups/ (features for grouping, isolation 70545ce80fbSLi Zefan and resource control) 706ddbcc7e8SPaul Menage 707ddbcc7e8SPaul Menage Say N if unsure. 708ddbcc7e8SPaul Menage 70923964d2dSLi Zefanif CGROUPS 71023964d2dSLi Zefan 711006cb992SPaul Menageconfig CGROUP_DEBUG 712006cb992SPaul Menage bool "Example debug cgroup subsystem" 713418d7d87SPaul Menage default n 714006cb992SPaul Menage help 715006cb992SPaul Menage This option enables a simple cgroup subsystem that 716006cb992SPaul Menage exports useful debugging information about the cgroups 71723964d2dSLi Zefan framework. 718006cb992SPaul Menage 71923964d2dSLi Zefan Say N if unsure. 720006cb992SPaul Menage 721dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER 72223964d2dSLi Zefan bool "Freezer cgroup subsystem" 723dc52ddc0SMatt Helsley help 724dc52ddc0SMatt Helsley Provides a way to freeze and unfreeze all tasks in a 725dc52ddc0SMatt Helsley cgroup. 726dc52ddc0SMatt Helsley 72708ce5f16SSerge E. Hallynconfig CGROUP_DEVICE 72808ce5f16SSerge E. Hallyn bool "Device controller for cgroups" 72908ce5f16SSerge E. Hallyn help 73008ce5f16SSerge E. Hallyn Provides a cgroup implementing whitelists for devices which 73108ce5f16SSerge E. Hallyn a process in the cgroup can mknod or open. 73208ce5f16SSerge E. Hallyn 7331da177e4SLinus Torvaldsconfig CPUSETS 7341da177e4SLinus Torvalds bool "Cpuset support" 7351da177e4SLinus Torvalds help 736d9fd8a6dSRandy Dunlap This option will let you create and manage CPUSETs which 7371da177e4SLinus Torvalds allow dynamically partitioning a system into sets of CPUs and 7381da177e4SLinus Torvalds Memory Nodes and assigning tasks to run only within those sets. 7391da177e4SLinus Torvalds This is primarily useful on large SMP or NUMA systems. 7401da177e4SLinus Torvalds 7411da177e4SLinus Torvalds Say N if unsure. 7421da177e4SLinus Torvalds 74323964d2dSLi Zefanconfig PROC_PID_CPUSET 74423964d2dSLi Zefan bool "Include legacy /proc/<pid>/cpuset file" 74523964d2dSLi Zefan depends on CPUSETS 74623964d2dSLi Zefan default y 74723964d2dSLi Zefan 748d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT 749d842de87SSrivatsa Vaddagiri bool "Simple CPU accounting cgroup subsystem" 750d842de87SSrivatsa Vaddagiri help 751d842de87SSrivatsa Vaddagiri Provides a simple Resource Controller for monitoring the 75223964d2dSLi Zefan total CPU consumed by the tasks in a cgroup. 753d842de87SSrivatsa Vaddagiri 754e552b661SPavel Emelianovconfig RESOURCE_COUNTERS 755e552b661SPavel Emelianov bool "Resource counters" 756e552b661SPavel Emelianov help 757e552b661SPavel Emelianov This option enables controller independent resource accounting 75823964d2dSLi Zefan infrastructure that works with cgroups. 759e552b661SPavel Emelianov 760c255a458SAndrew Mortonconfig MEMCG 76100f0b825SBalbir Singh bool "Memory Resource Controller for Control Groups" 76279ae9c29SDaniel Lezcano depends on RESOURCE_COUNTERS 763cf475ad2SBalbir Singh select MM_OWNER 76400f0b825SBalbir Singh help 76584ad6d70SKAMEZAWA Hiroyuki Provides a memory resource controller that manages both anonymous 76621acb9caSThadeu Lima de Souza Cascardo memory and page cache. (See Documentation/cgroups/memory.txt) 76700f0b825SBalbir Singh 76800f0b825SBalbir Singh Note that setting this option increases fixed memory overhead 76984ad6d70SKAMEZAWA Hiroyuki associated with each page of memory in the system. By this, 77084ad6d70SKAMEZAWA Hiroyuki 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 77184ad6d70SKAMEZAWA Hiroyuki usage tracking struct at boot. Total amount of this is printed out 77284ad6d70SKAMEZAWA Hiroyuki at boot. 77300f0b825SBalbir Singh 77400f0b825SBalbir Singh Only enable when you're ok with these trade offs and really 77584ad6d70SKAMEZAWA Hiroyuki sure you need the memory resource controller. Even when you enable 77684ad6d70SKAMEZAWA Hiroyuki this, you can set "cgroup_disable=memory" at your boot option to 77784ad6d70SKAMEZAWA Hiroyuki disable memory resource controller and you can avoid overheads. 778c9d5409fSLi Zefan (and lose benefits of memory resource controller) 77900f0b825SBalbir Singh 780cf475ad2SBalbir Singh This config option also selects MM_OWNER config option, which 781cf475ad2SBalbir Singh could in turn add some fork/exit overhead. 782cf475ad2SBalbir Singh 783c255a458SAndrew Mortonconfig MEMCG_SWAP 78465e0e811SKAMEZAWA Hiroyuki bool "Memory Resource Controller Swap Extension" 785c255a458SAndrew Morton depends on MEMCG && SWAP 786c077719bSKAMEZAWA Hiroyuki help 787c077719bSKAMEZAWA Hiroyuki Add swap management feature to memory resource controller. When you 788c077719bSKAMEZAWA Hiroyuki enable this, you can limit mem+swap usage per cgroup. In other words, 789c077719bSKAMEZAWA Hiroyuki when you disable this, memory resource controller has no cares to 790c077719bSKAMEZAWA Hiroyuki usage of swap...a process can exhaust all of the swap. This extension 791c077719bSKAMEZAWA Hiroyuki is useful when you want to avoid exhaustion swap but this itself 792c077719bSKAMEZAWA Hiroyuki adds more overheads and consumes memory for remembering information. 793c077719bSKAMEZAWA Hiroyuki Especially if you use 32bit system or small memory system, please 794c077719bSKAMEZAWA Hiroyuki be careful about enabling this. When memory resource controller 795c077719bSKAMEZAWA Hiroyuki is disabled by boot option, this will be automatically disabled and 796c077719bSKAMEZAWA Hiroyuki there will be no overhead from this. Even when you set this config=y, 79700a66d29SWANG Cong if boot option "swapaccount=0" is set, swap will not be accounted. 798627991a2SKAMEZAWA Hiroyuki Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page 799627991a2SKAMEZAWA Hiroyuki size is 4096bytes, 512k per 1Gbytes of swap. 800c255a458SAndrew Mortonconfig MEMCG_SWAP_ENABLED 801a42c390cSMichal Hocko bool "Memory Resource Controller Swap Extension enabled by default" 802c255a458SAndrew Morton depends on MEMCG_SWAP 803a42c390cSMichal Hocko default y 804a42c390cSMichal Hocko help 805a42c390cSMichal Hocko Memory Resource Controller Swap Extension comes with its price in 806a42c390cSMichal Hocko a bigger memory consumption. General purpose distribution kernels 80743d547f9SJim Cromie which want to enable the feature but keep it disabled by default 808a42c390cSMichal Hocko and let the user enable it by swapaccount boot command line 809a42c390cSMichal Hocko parameter should have this option unselected. 810a42c390cSMichal Hocko For those who want to have the feature enabled by default should 811a42c390cSMichal Hocko select this option (if, for some reason, they need to disable it 81200a66d29SWANG Cong then swapaccount=0 does the trick). 813c255a458SAndrew Mortonconfig MEMCG_KMEM 814e5671dfaSGlauber Costa bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)" 815c255a458SAndrew Morton depends on MEMCG && EXPERIMENTAL 816e5671dfaSGlauber Costa default n 817e5671dfaSGlauber Costa help 818e5671dfaSGlauber Costa The Kernel Memory extension for Memory Resource Controller can limit 819e5671dfaSGlauber Costa the amount of memory used by kernel objects in the system. Those are 820e5671dfaSGlauber Costa fundamentally different from the entities handled by the standard 821e5671dfaSGlauber Costa Memory Controller, which are page-based, and can be swapped. Users of 822e5671dfaSGlauber Costa the kmem extension can use it to guarantee that no group of processes 823e5671dfaSGlauber Costa will ever exhaust kernel resources alone. 824c077719bSKAMEZAWA Hiroyuki 8252bc64a20SAneesh Kumar K.Vconfig CGROUP_HUGETLB 8262bc64a20SAneesh Kumar K.V bool "HugeTLB Resource Controller for Control Groups" 8272bc64a20SAneesh Kumar K.V depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL 8282bc64a20SAneesh Kumar K.V default n 8292bc64a20SAneesh Kumar K.V help 8302bc64a20SAneesh Kumar K.V Provides a cgroup Resource Controller for HugeTLB pages. 8312bc64a20SAneesh Kumar K.V When you enable this, you can put a per cgroup limit on HugeTLB usage. 8322bc64a20SAneesh Kumar K.V The limit is enforced during page fault. Since HugeTLB doesn't 8332bc64a20SAneesh Kumar K.V support page reclaim, enforcing the limit at page fault time implies 8342bc64a20SAneesh Kumar K.V that, the application will get SIGBUS signal if it tries to access 8352bc64a20SAneesh Kumar K.V HugeTLB pages beyond its limit. This requires the application to know 8362bc64a20SAneesh Kumar K.V beforehand how much HugeTLB pages it would require for its use. The 8372bc64a20SAneesh Kumar K.V control group is tracked in the third page lru pointer. This means 8382bc64a20SAneesh Kumar K.V that we cannot use the controller with huge page less than 3 pages. 8392bc64a20SAneesh Kumar K.V 840e5d1367fSStephane Eranianconfig CGROUP_PERF 841e5d1367fSStephane Eranian bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" 842e5d1367fSStephane Eranian depends on PERF_EVENTS && CGROUPS 843e5d1367fSStephane Eranian help 844e5d1367fSStephane Eranian This option extends the per-cpu mode to restrict monitoring to 8452d0f2520SLi Zefan threads which belong to the cgroup specified and run on the 846e5d1367fSStephane Eranian designated cpu. 847e5d1367fSStephane Eranian 848e5d1367fSStephane Eranian Say N if unsure. 849e5d1367fSStephane Eranian 8507c941438SDhaval Gianimenuconfig CGROUP_SCHED 8517c941438SDhaval Giani bool "Group CPU scheduler" 8527c941438SDhaval Giani default n 8537c941438SDhaval Giani help 8547c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 8557c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 8567c941438SDhaval Giani tasks. 8577c941438SDhaval Giani 8587c941438SDhaval Gianiif CGROUP_SCHED 8597c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 8607c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 8617c941438SDhaval Giani depends on CGROUP_SCHED 8627c941438SDhaval Giani default CGROUP_SCHED 8637c941438SDhaval Giani 864ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 865ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 866ab84d31eSPaul Turner depends on EXPERIMENTAL 867ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 868ab84d31eSPaul Turner default n 869ab84d31eSPaul Turner help 870ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 871ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 872ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 873ab84d31eSPaul Turner restriction. 874ab84d31eSPaul Turner See tip/Documentation/scheduler/sched-bwc.txt for more information. 875ab84d31eSPaul Turner 8767c941438SDhaval Gianiconfig RT_GROUP_SCHED 8777c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 8787c941438SDhaval Giani depends on EXPERIMENTAL 8797c941438SDhaval Giani depends on CGROUP_SCHED 8807c941438SDhaval Giani default n 8817c941438SDhaval Giani help 8827c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 88332bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 8847c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 8857c941438SDhaval Giani realtime bandwidth for them. 8867c941438SDhaval Giani See Documentation/scheduler/sched-rt-group.txt for more information. 8877c941438SDhaval Giani 8887c941438SDhaval Gianiendif #CGROUP_SCHED 8897c941438SDhaval Giani 890afc24d49SVivek Goyalconfig BLK_CGROUP 89132e380aeSTejun Heo bool "Block IO controller" 89279ae9c29SDaniel Lezcano depends on BLOCK 893afc24d49SVivek Goyal default n 894afc24d49SVivek Goyal ---help--- 895afc24d49SVivek Goyal Generic block IO controller cgroup interface. This is the common 896afc24d49SVivek Goyal cgroup interface which should be used by various IO controlling 897afc24d49SVivek Goyal policies. 898afc24d49SVivek Goyal 899afc24d49SVivek Goyal Currently, CFQ IO scheduler uses it to recognize task groups and 900afc24d49SVivek Goyal control disk bandwidth allocation (proportional time slice allocation) 901e43473b7SVivek Goyal to such task groups. It is also used by bio throttling logic in 902e43473b7SVivek Goyal block layer to implement upper limit in IO rates on a device. 903afc24d49SVivek Goyal 904afc24d49SVivek Goyal This option only enables generic Block IO controller infrastructure. 905e43473b7SVivek Goyal One needs to also enable actual IO controlling logic/policy. For 90679e2e759SMichael Witten enabling proportional weight division of disk bandwidth in CFQ, set 90779e2e759SMichael Witten CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 908c5e0591aSMichael Witten CONFIG_BLK_DEV_THROTTLING=y. 909afc24d49SVivek Goyal 910afc24d49SVivek Goyal See Documentation/cgroups/blkio-controller.txt for more information. 911afc24d49SVivek Goyal 912afc24d49SVivek Goyalconfig DEBUG_BLK_CGROUP 913afc24d49SVivek Goyal bool "Enable Block IO controller debugging" 914afc24d49SVivek Goyal depends on BLK_CGROUP 915afc24d49SVivek Goyal default n 916afc24d49SVivek Goyal ---help--- 917afc24d49SVivek Goyal Enable some debugging help. Currently it exports additional stat 918afc24d49SVivek Goyal files in a cgroup which can be useful for debugging. 919afc24d49SVivek Goyal 92023964d2dSLi Zefanendif # CGROUPS 921c077719bSKAMEZAWA Hiroyuki 922067bce1aSCyrill Gorcunovconfig CHECKPOINT_RESTORE 923067bce1aSCyrill Gorcunov bool "Checkpoint/restore support" if EXPERT 924067bce1aSCyrill Gorcunov default n 925067bce1aSCyrill Gorcunov help 926067bce1aSCyrill Gorcunov Enables additional kernel features in a sake of checkpoint/restore. 927067bce1aSCyrill Gorcunov In particular it adds auxiliary prctl codes to setup process text, 928067bce1aSCyrill Gorcunov data and heap segment sizes, and a few additional /proc filesystem 929067bce1aSCyrill Gorcunov entries. 930067bce1aSCyrill Gorcunov 931067bce1aSCyrill Gorcunov If unsure, say N here. 932067bce1aSCyrill Gorcunov 9338dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 9346a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 9356a108a14SDavid Rientjes default !EXPERT 936c5289a69SPavel Emelyanov help 937c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 938c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 939c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 940c5289a69SPavel Emelyanov different namespaces. 941c5289a69SPavel Emelyanov 9428dd2a82cSDaniel Lezcanoif NAMESPACES 9438dd2a82cSDaniel Lezcano 94458bfdd6dSPavel Emelyanovconfig UTS_NS 94558bfdd6dSPavel Emelyanov bool "UTS namespace" 94617a6d441SDaniel Lezcano default y 94758bfdd6dSPavel Emelyanov help 94858bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 94958bfdd6dSPavel Emelyanov uname() system call 95058bfdd6dSPavel Emelyanov 951ae5e1b22SPavel Emelyanovconfig IPC_NS 952ae5e1b22SPavel Emelyanov bool "IPC namespace" 9538dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 95417a6d441SDaniel Lezcano default y 955ae5e1b22SPavel Emelyanov help 956ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 957614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 958ae5e1b22SPavel Emelyanov 959aee16ce7SPavel Emelyanovconfig USER_NS 960aee16ce7SPavel Emelyanov bool "User namespace (EXPERIMENTAL)" 9618dd2a82cSDaniel Lezcano depends on EXPERIMENTAL 962e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 9635673a94cSEric W. Biederman select UIDGID_STRICT_TYPE_CHECKS 964e1c972b6SEric W. Biederman 9655673a94cSEric W. Biederman default n 966aee16ce7SPavel Emelyanov help 967aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 968aee16ce7SPavel Emelyanov to provide different user info for different servers. 969aee16ce7SPavel Emelyanov If unsure, say N. 970aee16ce7SPavel Emelyanov 97174bd59bbSPavel Emelyanovconfig PID_NS 9729bd38c2cSDaniel Lezcano bool "PID Namespaces" 97317a6d441SDaniel Lezcano default y 97474bd59bbSPavel Emelyanov help 97512d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 976692105b8SMatt LaPlante processes with the same pid as long as they are in different 97774bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 97874bd59bbSPavel Emelyanov 979d6eb633fSMatt Helsleyconfig NET_NS 980d6eb633fSMatt Helsley bool "Network namespace" 9818dd2a82cSDaniel Lezcano depends on NET 98217a6d441SDaniel Lezcano default y 983d6eb633fSMatt Helsley help 984d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 985d6eb633fSMatt Helsley of the network stack. 986d6eb633fSMatt Helsley 9878dd2a82cSDaniel Lezcanoendif # NAMESPACES 9888dd2a82cSDaniel Lezcano 989e1c972b6SEric W. Biedermanconfig UIDGID_CONVERTED 990e1c972b6SEric W. Biederman # True if all of the selected software conmponents are known 991e1c972b6SEric W. Biederman # to have uid_t and gid_t converted to kuid_t and kgid_t 992e1c972b6SEric W. Biederman # where appropriate and are otherwise safe to use with 993e1c972b6SEric W. Biederman # the user namespace. 994e1c972b6SEric W. Biederman bool 995e1c972b6SEric W. Biederman default y 996e1c972b6SEric W. Biederman 997e1c972b6SEric W. Biederman # Networking 998e1c972b6SEric W. Biederman depends on NET_9P = n 999e1c972b6SEric W. Biederman 1000e1c972b6SEric W. Biederman # Filesystems 1001e1c972b6SEric W. Biederman depends on 9P_FS = n 1002e1c972b6SEric W. Biederman depends on AFS_FS = n 1003e1c972b6SEric W. Biederman depends on AUTOFS4_FS = n 1004e1c972b6SEric W. Biederman depends on CEPH_FS = n 1005e1c972b6SEric W. Biederman depends on CIFS = n 1006e1c972b6SEric W. Biederman depends on CODA_FS = n 1007e1c972b6SEric W. Biederman depends on FUSE_FS = n 1008e1c972b6SEric W. Biederman depends on GFS2_FS = n 1009e1c972b6SEric W. Biederman depends on NCP_FS = n 1010e1c972b6SEric W. Biederman depends on NFSD = n 1011e1c972b6SEric W. Biederman depends on NFS_FS = n 1012e1c972b6SEric W. Biederman depends on OCFS2_FS = n 1013e1c972b6SEric W. Biederman depends on XFS_FS = n 1014e1c972b6SEric W. Biederman 10155673a94cSEric W. Biedermanconfig UIDGID_STRICT_TYPE_CHECKS 10165673a94cSEric W. Biederman bool "Require conversions between uid/gids and their internal representation" 1017e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 10185673a94cSEric W. Biederman default n 10195673a94cSEric W. Biederman help 10205673a94cSEric W. Biederman While the nececessary conversions are being added to all subsystems this option allows 10215673a94cSEric W. Biederman the code to continue to build for unconverted subsystems. 10225673a94cSEric W. Biederman 10235673a94cSEric W. Biederman Say Y here if you want the strict type checking enabled 10245673a94cSEric W. Biederman 10255091faa4SMike Galbraithconfig SCHED_AUTOGROUP 10265091faa4SMike Galbraith bool "Automatic process group scheduling" 10275091faa4SMike Galbraith select EVENTFD 10285091faa4SMike Galbraith select CGROUPS 10295091faa4SMike Galbraith select CGROUP_SCHED 10305091faa4SMike Galbraith select FAIR_GROUP_SCHED 10315091faa4SMike Galbraith help 10325091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 10335091faa4SMike Galbraith automatically creating and populating task groups. This separation 10345091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 10355091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 10365091faa4SMike Galbraith upon task session. 10375091faa4SMike Galbraith 10387af37becSDaniel Lezcanoconfig MM_OWNER 10397af37becSDaniel Lezcano bool 10407af37becSDaniel Lezcano 10417af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED 10425d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features to support old userspace tools" 10437af37becSDaniel Lezcano depends on SYSFS 10447af37becSDaniel Lezcano default n 10457af37becSDaniel Lezcano help 10467af37becSDaniel Lezcano This option adds code that switches the layout of the "block" class 10477af37becSDaniel Lezcano devices, to not show up in /sys/class/block/, but only in 10487af37becSDaniel Lezcano /sys/block/. 10497af37becSDaniel Lezcano 10507af37becSDaniel Lezcano This switch is only active when the sysfs.deprecated=1 boot option is 10517af37becSDaniel Lezcano passed or the SYSFS_DEPRECATED_V2 option is set. 10527af37becSDaniel Lezcano 10537af37becSDaniel Lezcano This option allows new kernels to run on old distributions and tools, 10547af37becSDaniel Lezcano which might get confused by /sys/class/block/. Since 2007/2008 all 10557af37becSDaniel Lezcano major distributions and tools handle this just fine. 10567af37becSDaniel Lezcano 10577af37becSDaniel Lezcano Recent distributions and userspace tools after 2009/2010 depend on 10587af37becSDaniel Lezcano the existence of /sys/class/block/, and will not work with this 10597af37becSDaniel Lezcano option enabled. 10607af37becSDaniel Lezcano 10617af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 10627af37becSDaniel Lezcano need to say Y here. 10637af37becSDaniel Lezcano 10647af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED_V2 10655d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features by default" 10667af37becSDaniel Lezcano default n 10677af37becSDaniel Lezcano depends on SYSFS 10687af37becSDaniel Lezcano depends on SYSFS_DEPRECATED 10697af37becSDaniel Lezcano help 10707af37becSDaniel Lezcano Enable deprecated sysfs by default. 10717af37becSDaniel Lezcano 10727af37becSDaniel Lezcano See the CONFIG_SYSFS_DEPRECATED option for more details about this 10737af37becSDaniel Lezcano option. 10747af37becSDaniel Lezcano 10757af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 10767af37becSDaniel Lezcano need to say Y here. Even then, odds are you would not need it 10777af37becSDaniel Lezcano enabled, you can always pass the boot option if absolutely necessary. 10787af37becSDaniel Lezcano 10797af37becSDaniel Lezcanoconfig RELAY 10807af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 10817af37becSDaniel Lezcano help 10827af37becSDaniel Lezcano This option enables support for relay interface support in 10837af37becSDaniel Lezcano certain file systems (such as debugfs). 10847af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 10857af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 10867af37becSDaniel Lezcano user space. 10877af37becSDaniel Lezcano 10887af37becSDaniel Lezcano If unsure, say N. 10897af37becSDaniel Lezcano 1090f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1091f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1092f991633dSDimitri Gorokhovik depends on BROKEN || !FRV 1093f991633dSDimitri Gorokhovik help 1094f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1095f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1096f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1097f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 1098f991633dSDimitri Gorokhovik etc. See <file:Documentation/initrd.txt> for details. 1099f991633dSDimitri Gorokhovik 1100f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1101f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1102f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1103f991633dSDimitri Gorokhovik 1104f991633dSDimitri Gorokhovik If unsure say Y. 1105f991633dSDimitri Gorokhovik 1106c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1107c33df4eaSJean-Paul Saman 1108dbec4866SSam Ravnborgsource "usr/Kconfig" 1109dbec4866SSam Ravnborg 1110c33df4eaSJean-Paul Samanendif 1111c33df4eaSJean-Paul Saman 1112c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 111396fffeb4SIngo Molnar bool "Optimize for size" 1114c45b4f1fSLinus Torvalds help 1115c45b4f1fSLinus Torvalds Enabling this option will pass "-Os" instead of "-O2" to gcc 1116c45b4f1fSLinus Torvalds resulting in a smaller kernel. 1117c45b4f1fSLinus Torvalds 1118775a7229Sjkacur If unsure, say Y. 1119c45b4f1fSLinus Torvalds 11200847062aSRandy Dunlapconfig SYSCTL 11210847062aSRandy Dunlap bool 11220847062aSRandy Dunlap 1123b943c460SRandy Dunlapconfig ANON_INODES 1124b943c460SRandy Dunlap bool 1125b943c460SRandy Dunlap 11266a108a14SDavid Rientjesmenuconfig EXPERT 11276a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1128f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1129f505c553SJosh Triplett select DEBUG_KERNEL 11301da177e4SLinus Torvalds help 11311da177e4SLinus Torvalds This option allows certain base kernel options and settings 11321da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 11331da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 11341da177e4SLinus Torvalds Only use this if you really know what you are doing. 11351da177e4SLinus Torvalds 1136af1839ebSCatalin Marinasconfig HAVE_UID16 1137af1839ebSCatalin Marinas bool 1138af1839ebSCatalin Marinas 1139ae81f9e3SChuck Ebbertconfig UID16 11406a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 1141af1839ebSCatalin Marinas depends on HAVE_UID16 1142ae81f9e3SChuck Ebbert default y 1143ae81f9e3SChuck Ebbert help 1144ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1145ae81f9e3SChuck Ebbert 1146b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL 11476a108a14SDavid Rientjes bool "Sysctl syscall support" if EXPERT 114826a7034bSEric W. Biederman depends on PROC_SYSCTL 1149c736de60SWANG Cong default n 1150b89a8171SEric W. Biederman select SYSCTL 1151b89a8171SEric W. Biederman ---help--- 115213bb7e37SEric W. Biederman sys_sysctl uses binary paths that have been found challenging 115313bb7e37SEric W. Biederman to properly maintain and use. The interface in /proc/sys 115413bb7e37SEric W. Biederman using paths with ascii names is now the primary path to this 115513bb7e37SEric W. Biederman information. 1156b89a8171SEric W. Biederman 115713bb7e37SEric W. Biederman Almost nothing using the binary sysctl interface so if you are 115813bb7e37SEric W. Biederman trying to save some space it is probably safe to disable this, 115913bb7e37SEric W. Biederman making your kernel marginally smaller. 1160b89a8171SEric W. Biederman 1161c736de60SWANG Cong If unsure say N here. 1162ae81f9e3SChuck Ebbert 11637ac57a89SCatalin Marinasconfig SYSCTL_EXCEPTION_TRACE 11647ac57a89SCatalin Marinas bool 11657ac57a89SCatalin Marinas help 11667ac57a89SCatalin Marinas Enable support for /proc/sys/debug/exception-trace. 11677ac57a89SCatalin Marinas 11681da177e4SLinus Torvaldsconfig KALLSYMS 11696a108a14SDavid Rientjes bool "Load all symbols for debugging/ksymoops" if EXPERT 11701da177e4SLinus Torvalds default y 11711da177e4SLinus Torvalds help 11721da177e4SLinus Torvalds Say Y here to let the kernel print out symbolic crash information and 11731da177e4SLinus Torvalds symbolic stack backtraces. This increases the size of the kernel 11741da177e4SLinus Torvalds somewhat, as all symbols have to be loaded into the kernel image. 11751da177e4SLinus Torvalds 11761da177e4SLinus Torvaldsconfig KALLSYMS_ALL 11771da177e4SLinus Torvalds bool "Include all symbols in kallsyms" 11781da177e4SLinus Torvalds depends on DEBUG_KERNEL && KALLSYMS 11791da177e4SLinus Torvalds help 118071a83ec7SArtem Bityutskiy Normally kallsyms only contains the symbols of functions for nicer 118171a83ec7SArtem Bityutskiy OOPS messages and backtraces (i.e., symbols from the text and inittext 118271a83ec7SArtem Bityutskiy sections). This is sufficient for most cases. And only in very rare 118371a83ec7SArtem Bityutskiy cases (e.g., when a debugger is used) all symbols are required (e.g., 118471a83ec7SArtem Bityutskiy names of variables from the data sections, etc). 11851da177e4SLinus Torvalds 118671a83ec7SArtem Bityutskiy This option makes sure that all symbols are loaded into the kernel 118771a83ec7SArtem Bityutskiy image (i.e., symbols from all sections) in cost of increased kernel 118871a83ec7SArtem Bityutskiy size (depending on the kernel configuration, it may be 300KiB or 118971a83ec7SArtem Bityutskiy something like this). 11901da177e4SLinus Torvalds 119171a83ec7SArtem Bityutskiy Say N unless you really need all symbols. 1192d59745ceSMatt Mackall 1193712f47ceSGreg Kroah-Hartmanconfig HOTPLUG 119445f035abSGreg Kroah-Hartman def_bool y 1195712f47ceSGreg Kroah-Hartman 1196d59745ceSMatt Mackallconfig PRINTK 1197d59745ceSMatt Mackall default y 11986a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 1199*74876a98SFrederic Weisbecker select IRQ_WORK 1200d59745ceSMatt Mackall help 1201d59745ceSMatt Mackall This option enables normal printk support. Removing it 1202d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1203d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1204d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1205d59745ceSMatt Mackall strongly discouraged. 1206d59745ceSMatt Mackall 1207c8538a7aSMatt Mackallconfig BUG 12086a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1209c8538a7aSMatt Mackall default y 1210c8538a7aSMatt Mackall help 1211c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1212c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1213c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1214c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1215c8538a7aSMatt Mackall Just say Y. 1216c8538a7aSMatt Mackall 1217708e9a79SMatt Mackallconfig ELF_CORE 1218046d662fSAlex Kelly depends on COREDUMP 1219708e9a79SMatt Mackall default y 12206a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1221708e9a79SMatt Mackall help 1222708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1223708e9a79SMatt Mackall 12248761f1abSRalf Baechle 1225e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 12266a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 12278761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 122815f304b6SRalf Baechle select I8253_LOCK 1229e5e1d3cbSStas Sergeev default y 1230e5e1d3cbSStas Sergeev help 1231e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1232e5e1d3cbSStas Sergeev support, saving some memory. 1233e5e1d3cbSStas Sergeev 12348761f1abSRalf Baechleconfig HAVE_PCSPKR_PLATFORM 12358761f1abSRalf Baechle bool 12368761f1abSRalf Baechle 12371da177e4SLinus Torvaldsconfig BASE_FULL 12381da177e4SLinus Torvalds default y 12396a108a14SDavid Rientjes bool "Enable full-sized data structures for core" if EXPERT 12401da177e4SLinus Torvalds help 12411da177e4SLinus Torvalds Disabling this option reduces the size of miscellaneous core 12421da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 12431da177e4SLinus Torvalds but may reduce performance. 12441da177e4SLinus Torvalds 12451da177e4SLinus Torvaldsconfig FUTEX 12466a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 12471da177e4SLinus Torvalds default y 124823f78d4aSIngo Molnar select RT_MUTEXES 12491da177e4SLinus Torvalds help 12501da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 12511da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 12521da177e4SLinus Torvalds run glibc-based applications correctly. 12531da177e4SLinus Torvalds 12541da177e4SLinus Torvaldsconfig EPOLL 12556a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 12561da177e4SLinus Torvalds default y 1257448e3ceeSAdrian Bunk select ANON_INODES 12581da177e4SLinus Torvalds help 12591da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 12601da177e4SLinus Torvalds support for epoll family of system calls. 12611da177e4SLinus Torvalds 1262fba2afaaSDavide Libenziconfig SIGNALFD 12636a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1264448e3ceeSAdrian Bunk select ANON_INODES 1265fba2afaaSDavide Libenzi default y 1266fba2afaaSDavide Libenzi help 1267fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1268fba2afaaSDavide Libenzi on a file descriptor. 1269fba2afaaSDavide Libenzi 1270fba2afaaSDavide Libenzi If unsure, say Y. 1271fba2afaaSDavide Libenzi 1272b215e283SDavide Libenziconfig TIMERFD 12736a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1274448e3ceeSAdrian Bunk select ANON_INODES 1275b215e283SDavide Libenzi default y 1276b215e283SDavide Libenzi help 1277b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1278b215e283SDavide Libenzi events on a file descriptor. 1279b215e283SDavide Libenzi 1280b215e283SDavide Libenzi If unsure, say Y. 1281b215e283SDavide Libenzi 1282e1ad7468SDavide Libenziconfig EVENTFD 12836a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1284448e3ceeSAdrian Bunk select ANON_INODES 1285e1ad7468SDavide Libenzi default y 1286e1ad7468SDavide Libenzi help 1287e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1288e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1289e1ad7468SDavide Libenzi 1290e1ad7468SDavide Libenzi If unsure, say Y. 1291e1ad7468SDavide Libenzi 12921da177e4SLinus Torvaldsconfig SHMEM 12936a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 12941da177e4SLinus Torvalds default y 12951da177e4SLinus Torvalds depends on MMU 12961da177e4SLinus Torvalds help 12971da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 12981da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 12991da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 13001da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 13011da177e4SLinus Torvalds which may be appropriate on small systems without swap. 13021da177e4SLinus Torvalds 1303ebf3f09cSThomas Petazzoniconfig AIO 13046a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1305ebf3f09cSThomas Petazzoni default y 1306ebf3f09cSThomas Petazzoni help 1307ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1308ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1309ebf3f09cSThomas Petazzoni this option saves about 7k. 1310ebf3f09cSThomas Petazzoni 13116befe5f6SRandy Dunlapconfig EMBEDDED 13126befe5f6SRandy Dunlap bool "Embedded system" 13136befe5f6SRandy Dunlap select EXPERT 13146befe5f6SRandy Dunlap help 13156befe5f6SRandy Dunlap This option should be enabled if compiling the kernel for 13166befe5f6SRandy Dunlap an embedded system so certain expert options are available 13176befe5f6SRandy Dunlap for configuration. 13186befe5f6SRandy Dunlap 1319cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 13200793a61dSThomas Gleixner bool 1321018df72dSMike Frysinger help 1322018df72dSMike Frysinger See tools/perf/design.txt for details. 13230793a61dSThomas Gleixner 1324906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 1325906010b2SPeter Zijlstra bool 1326906010b2SPeter Zijlstra help 1327906010b2SPeter Zijlstra See tools/perf/design.txt for details 1328906010b2SPeter Zijlstra 132957c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 13300793a61dSThomas Gleixner 1331cdd6c482SIngo Molnarconfig PERF_EVENTS 133257c0c15bSIngo Molnar bool "Kernel performance events and counters" 1333392d65a9SRobert Richter default y if PROFILING 1334cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 13354c59e467SIngo Molnar select ANON_INODES 1336e360adbeSPeter Zijlstra select IRQ_WORK 13370793a61dSThomas Gleixner help 133857c0c15bSIngo Molnar Enable kernel support for various performance events provided 133957c0c15bSIngo Molnar by software and hardware. 13400793a61dSThomas Gleixner 1341dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 134257c0c15bSIngo Molnar use of generic tracepoints. 134357c0c15bSIngo Molnar 134457c0c15bSIngo Molnar Most modern CPUs support performance events via performance 134557c0c15bSIngo Molnar counter registers. These registers count the number of certain 13460793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 13470793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 13480793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 13490793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 13500793a61dSThomas Gleixner used to profile the code that runs on that CPU. 13510793a61dSThomas Gleixner 135257c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 1353dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 135457c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 13550793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 13560793a61dSThomas Gleixner capabilities on top of those. 13570793a61dSThomas Gleixner 13580793a61dSThomas Gleixner Say Y if unsure. 13590793a61dSThomas Gleixner 1360906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 1361906010b2SPeter Zijlstra default n 1362906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 1363906010b2SPeter Zijlstra depends on PERF_EVENTS && DEBUG_KERNEL 1364906010b2SPeter Zijlstra select PERF_USE_VMALLOC 1365906010b2SPeter Zijlstra help 1366906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 1367906010b2SPeter Zijlstra 1368906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 1369906010b2SPeter Zijlstra that don't require it. 1370906010b2SPeter Zijlstra 1371906010b2SPeter Zijlstra Say N if unsure. 1372906010b2SPeter Zijlstra 13730793a61dSThomas Gleixnerendmenu 13740793a61dSThomas Gleixner 1375f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS 1376f8891e5eSChristoph Lameter default y 13776a108a14SDavid Rientjes bool "Enable VM event counters for /proc/vmstat" if EXPERT 1378f8891e5eSChristoph Lameter help 13792aea4fb6SPaul Jackson VM event counters are needed for event counts to be shown. 13802aea4fb6SPaul Jackson This option allows the disabling of the VM event counters 13816a108a14SDavid Rientjes on EXPERT systems. /proc/vmstat will only show page counts 13822aea4fb6SPaul Jackson if VM event counters are disabled. 1383f8891e5eSChristoph Lameter 13843d137310SThomas Petazzoniconfig PCI_QUIRKS 13853d137310SThomas Petazzoni default y 13866a108a14SDavid Rientjes bool "Enable PCI quirk workarounds" if EXPERT 138761cfc7e4SGeert Uytterhoeven depends on PCI 13883d137310SThomas Petazzoni help 13893d137310SThomas Petazzoni This enables workarounds for various PCI chipset 13903d137310SThomas Petazzoni bugs/quirks. Disable this only if your target machine is 13913d137310SThomas Petazzoni unaffected by PCI quirks. 13923d137310SThomas Petazzoni 139341ecc55bSChristoph Lameterconfig SLUB_DEBUG 139441ecc55bSChristoph Lameter default y 13956a108a14SDavid Rientjes bool "Enable SLUB debugging support" if EXPERT 1396f6acb635SChristoph Lameter depends on SLUB && SYSFS 139741ecc55bSChristoph Lameter help 139841ecc55bSChristoph Lameter SLUB has extensive debug support features. Disabling these can 139941ecc55bSChristoph Lameter result in significant savings in code size. This also disables 140041ecc55bSChristoph Lameter SLUB sysfs support. /sys/slab will not exist and there will be 140141ecc55bSChristoph Lameter no support for cache validation etc. 140241ecc55bSChristoph Lameter 1403b943c460SRandy Dunlapconfig COMPAT_BRK 1404b943c460SRandy Dunlap bool "Disable heap randomization" 1405b943c460SRandy Dunlap default y 1406b943c460SRandy Dunlap help 1407b943c460SRandy Dunlap Randomizing heap placement makes heap exploits harder, but it 1408b943c460SRandy Dunlap also breaks ancient binaries (including anything libc5 based). 1409b943c460SRandy Dunlap This option changes the bootup default to heap randomization 1410692105b8SMatt LaPlante disabled, and can be overridden at runtime by setting 1411b943c460SRandy Dunlap /proc/sys/kernel/randomize_va_space to 2. 1412b943c460SRandy Dunlap 1413b943c460SRandy Dunlap On non-ancient distros (post-2000 ones) N is usually a safe choice. 1414b943c460SRandy Dunlap 141581819f0fSChristoph Lameterchoice 141681819f0fSChristoph Lameter prompt "Choose SLAB allocator" 1417a0acd820SChristoph Lameter default SLUB 141881819f0fSChristoph Lameter help 141981819f0fSChristoph Lameter This option allows to select a slab allocator. 142081819f0fSChristoph Lameter 142181819f0fSChristoph Lameterconfig SLAB 142281819f0fSChristoph Lameter bool "SLAB" 142381819f0fSChristoph Lameter help 142481819f0fSChristoph Lameter The regular slab allocator that is established and known to work 142534013886SChristoph Lameter well in all environments. It organizes cache hot objects in 142602f56210SSimon Arlott per cpu and per node queues. 142781819f0fSChristoph Lameter 142881819f0fSChristoph Lameterconfig SLUB 142981819f0fSChristoph Lameter bool "SLUB (Unqueued Allocator)" 143081819f0fSChristoph Lameter help 143181819f0fSChristoph Lameter SLUB is a slab allocator that minimizes cache line usage 143281819f0fSChristoph Lameter instead of managing queues of cached objects (SLAB approach). 143381819f0fSChristoph Lameter Per cpu caching is realized using slabs of objects instead 143481819f0fSChristoph Lameter of queues of objects. SLUB can use memory efficiently 143502f56210SSimon Arlott and has enhanced diagnostics. SLUB is the default choice for 143602f56210SSimon Arlott a slab allocator. 143781819f0fSChristoph Lameter 143881819f0fSChristoph Lameterconfig SLOB 14396a108a14SDavid Rientjes depends on EXPERT 144081819f0fSChristoph Lameter bool "SLOB (Simple Allocator)" 144181819f0fSChristoph Lameter help 144237291458SMatt Mackall SLOB replaces the stock allocator with a drastically simpler 144337291458SMatt Mackall allocator. SLOB is generally more space efficient but 144437291458SMatt Mackall does not perform as well on large systems. 144581819f0fSChristoph Lameter 144681819f0fSChristoph Lameterendchoice 144781819f0fSChristoph Lameter 1448ea637639SJie Zhangconfig MMAP_ALLOW_UNINITIALIZED 1449ea637639SJie Zhang bool "Allow mmapped anonymous memory to be uninitialized" 14506a108a14SDavid Rientjes depends on EXPERT && !MMU 1451ea637639SJie Zhang default n 1452ea637639SJie Zhang help 1453ea637639SJie Zhang Normally, and according to the Linux spec, anonymous memory obtained 1454ea637639SJie Zhang from mmap() has it's contents cleared before it is passed to 1455ea637639SJie Zhang userspace. Enabling this config option allows you to request that 1456ea637639SJie Zhang mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus 1457ea637639SJie Zhang providing a huge performance boost. If this option is not enabled, 1458ea637639SJie Zhang then the flag will be ignored. 1459ea637639SJie Zhang 1460ea637639SJie Zhang This is taken advantage of by uClibc's malloc(), and also by 1461ea637639SJie Zhang ELF-FDPIC binfmt's brk and stack allocator. 1462ea637639SJie Zhang 1463ea637639SJie Zhang Because of the obvious security issues, this option should only be 1464ea637639SJie Zhang enabled on embedded devices where you control what is run in 1465ea637639SJie Zhang userspace. Since that isn't generally a problem on no-MMU systems, 1466ea637639SJie Zhang it is normally safe to say Y here. 1467ea637639SJie Zhang 1468ea637639SJie Zhang See Documentation/nommu-mmap.txt for more information. 1469ea637639SJie Zhang 1470125e5645SMathieu Desnoyersconfig PROFILING 1471b309a294SRobert Richter bool "Profiling support" 1472125e5645SMathieu Desnoyers help 1473125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 1474125e5645SMathieu Desnoyers by profilers such as OProfile. 1475125e5645SMathieu Desnoyers 14765f87f112SIngo Molnar# 14775f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 14785f87f112SIngo Molnar# dynamically changed for a probe function. 14795f87f112SIngo Molnar# 148097e1c18eSMathieu Desnoyersconfig TRACEPOINTS 14815f87f112SIngo Molnar bool 148297e1c18eSMathieu Desnoyers 1483fb32e03fSMathieu Desnoyerssource "arch/Kconfig" 1484fb32e03fSMathieu Desnoyers 14851da177e4SLinus Torvaldsendmenu # General setup 14861da177e4SLinus Torvalds 1487ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT 1488ee7e5516SDmitry Baryshkov bool 1489ee7e5516SDmitry Baryshkov default n 1490ee7e5516SDmitry Baryshkov 1491158a9624SLinus Torvaldsconfig SLABINFO 1492158a9624SLinus Torvalds bool 1493158a9624SLinus Torvalds depends on PROC_FS 14940f389ec6SChristoph Lameter depends on SLAB || SLUB_DEBUG 1495158a9624SLinus Torvalds default y 1496158a9624SLinus Torvalds 1497ae81f9e3SChuck Ebbertconfig RT_MUTEXES 1498ae81f9e3SChuck Ebbert boolean 1499ae81f9e3SChuck Ebbert 15001da177e4SLinus Torvaldsconfig BASE_SMALL 15011da177e4SLinus Torvalds int 15021da177e4SLinus Torvalds default 0 if BASE_FULL 15031da177e4SLinus Torvalds default 1 if !BASE_FULL 15041da177e4SLinus Torvalds 150566da5733SJan Engelhardtmenuconfig MODULES 15061da177e4SLinus Torvalds bool "Enable loadable module support" 15071da177e4SLinus Torvalds help 15081da177e4SLinus Torvalds Kernel modules are small pieces of compiled code which can 15091da177e4SLinus Torvalds be inserted in the running kernel, rather than being 15101da177e4SLinus Torvalds permanently built into the kernel. You use the "modprobe" 15111da177e4SLinus Torvalds tool to add (and sometimes remove) them. If you say Y here, 15121da177e4SLinus Torvalds many parts of the kernel can be built as modules (by 15131da177e4SLinus Torvalds answering M instead of Y where indicated): this is most 15141da177e4SLinus Torvalds useful for infrequently used options which are not required 15151da177e4SLinus Torvalds for booting. For more information, see the man pages for 15161da177e4SLinus Torvalds modprobe, lsmod, modinfo, insmod and rmmod. 15171da177e4SLinus Torvalds 15181da177e4SLinus Torvalds If you say Y here, you will need to run "make 15191da177e4SLinus Torvalds modules_install" to put the modules under /lib/modules/ 15201da177e4SLinus Torvalds where modprobe can find them (you may need to be root to do 15211da177e4SLinus Torvalds this). 15221da177e4SLinus Torvalds 15231da177e4SLinus Torvalds If unsure, say Y. 15241da177e4SLinus Torvalds 15250b0de144SRobert P. J. Dayif MODULES 15260b0de144SRobert P. J. Day 1527826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD 1528826e4506SLinus Torvalds bool "Forced module loading" 1529826e4506SLinus Torvalds default n 1530826e4506SLinus Torvalds help 153191e37a79SRusty Russell Allow loading of modules without version information (ie. modprobe 153291e37a79SRusty Russell --force). Forced module loading sets the 'F' (forced) taint flag and 153391e37a79SRusty Russell is usually a really bad idea. 1534826e4506SLinus Torvalds 15351da177e4SLinus Torvaldsconfig MODULE_UNLOAD 15361da177e4SLinus Torvalds bool "Module unloading" 15371da177e4SLinus Torvalds help 15381da177e4SLinus Torvalds Without this option you will not be able to unload any 15391da177e4SLinus Torvalds modules (note that some modules may not be unloadable 1540f7f5b675SDenys Vlasenko anyway), which makes your kernel smaller, faster 1541f7f5b675SDenys Vlasenko and simpler. If unsure, say Y. 15421da177e4SLinus Torvalds 15431da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD 15441da177e4SLinus Torvalds bool "Forced module unloading" 15451da177e4SLinus Torvalds depends on MODULE_UNLOAD && EXPERIMENTAL 15461da177e4SLinus Torvalds help 15471da177e4SLinus Torvalds This option allows you to force a module to unload, even if the 15481da177e4SLinus Torvalds kernel believes it is unsafe: the kernel will remove the module 15491da177e4SLinus Torvalds without waiting for anyone to stop using it (using the -f option to 15501da177e4SLinus Torvalds rmmod). This is mainly for kernel developers and desperate users. 15511da177e4SLinus Torvalds If unsure, say N. 15521da177e4SLinus Torvalds 15531da177e4SLinus Torvaldsconfig MODVERSIONS 15540d541643SSam Ravnborg bool "Module versioning support" 15551da177e4SLinus Torvalds help 15561da177e4SLinus Torvalds Usually, you have to use modules compiled with your kernel. 15571da177e4SLinus Torvalds Saying Y here makes it sometimes possible to use modules 15581da177e4SLinus Torvalds compiled for different kernels, by adding enough information 15591da177e4SLinus Torvalds to the modules to (hopefully) spot any changes which would 15601da177e4SLinus Torvalds make them incompatible with the kernel you are running. If 15611da177e4SLinus Torvalds unsure, say N. 15621da177e4SLinus Torvalds 15631da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL 15641da177e4SLinus Torvalds bool "Source checksum for all modules" 15651da177e4SLinus Torvalds help 15661da177e4SLinus Torvalds Modules which contain a MODULE_VERSION get an extra "srcversion" 15671da177e4SLinus Torvalds field inserted into their modinfo section, which contains a 15681da177e4SLinus Torvalds sum of the source files which made it. This helps maintainers 15691da177e4SLinus Torvalds see exactly which source was used to build a module (since 15701da177e4SLinus Torvalds others sometimes change the module source without updating 15711da177e4SLinus Torvalds the version). With this option, such a "srcversion" field 15721da177e4SLinus Torvalds will be created for all modules. If unsure, say N. 15731da177e4SLinus Torvalds 1574106a4ee2SRusty Russellconfig MODULE_SIG 1575106a4ee2SRusty Russell bool "Module signature verification" 1576106a4ee2SRusty Russell depends on MODULES 157748ba2462SDavid Howells select KEYS 157848ba2462SDavid Howells select CRYPTO 157948ba2462SDavid Howells select ASYMMETRIC_KEY_TYPE 158048ba2462SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 158148ba2462SDavid Howells select PUBLIC_KEY_ALGO_RSA 158248ba2462SDavid Howells select ASN1 158348ba2462SDavid Howells select OID_REGISTRY 158448ba2462SDavid Howells select X509_CERTIFICATE_PARSER 1585106a4ee2SRusty Russell help 1586106a4ee2SRusty Russell Check modules for valid signatures upon load: the signature 1587106a4ee2SRusty Russell is simply appended to the module. For more information see 1588106a4ee2SRusty Russell Documentation/module-signing.txt. 1589106a4ee2SRusty Russell 1590ea0b6dcfSDavid Howells !!!WARNING!!! If you enable this option, you MUST make sure that the 1591ea0b6dcfSDavid Howells module DOES NOT get stripped after being signed. This includes the 1592ea0b6dcfSDavid Howells debuginfo strip done by some packagers (such as rpmbuild) and 1593ea0b6dcfSDavid Howells inclusion into an initramfs that wants the module size reduced. 1594ea0b6dcfSDavid Howells 1595106a4ee2SRusty Russellconfig MODULE_SIG_FORCE 1596106a4ee2SRusty Russell bool "Require modules to be validly signed" 1597106a4ee2SRusty Russell depends on MODULE_SIG 1598106a4ee2SRusty Russell help 1599106a4ee2SRusty Russell Reject unsigned modules or signed modules for which we don't have a 1600106a4ee2SRusty Russell key. Without this, such modules will simply taint the kernel. 1601ea0b6dcfSDavid Howells 1602ea0b6dcfSDavid Howellschoice 1603ea0b6dcfSDavid Howells prompt "Which hash algorithm should modules be signed with?" 1604ea0b6dcfSDavid Howells depends on MODULE_SIG 1605ea0b6dcfSDavid Howells help 1606ea0b6dcfSDavid Howells This determines which sort of hashing algorithm will be used during 1607ea0b6dcfSDavid Howells signature generation. This algorithm _must_ be built into the kernel 1608ea0b6dcfSDavid Howells directly so that signature verification can take place. It is not 1609ea0b6dcfSDavid Howells possible to load a signed module containing the algorithm to check 1610ea0b6dcfSDavid Howells the signature on that module. 1611ea0b6dcfSDavid Howells 1612ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA1 1613ea0b6dcfSDavid Howells bool "Sign modules with SHA-1" 1614ea0b6dcfSDavid Howells select CRYPTO_SHA1 1615ea0b6dcfSDavid Howells 1616ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA224 1617ea0b6dcfSDavid Howells bool "Sign modules with SHA-224" 1618ea0b6dcfSDavid Howells select CRYPTO_SHA256 1619ea0b6dcfSDavid Howells 1620ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA256 1621ea0b6dcfSDavid Howells bool "Sign modules with SHA-256" 1622ea0b6dcfSDavid Howells select CRYPTO_SHA256 1623ea0b6dcfSDavid Howells 1624ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA384 1625ea0b6dcfSDavid Howells bool "Sign modules with SHA-384" 1626ea0b6dcfSDavid Howells select CRYPTO_SHA512 1627ea0b6dcfSDavid Howells 1628ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA512 1629ea0b6dcfSDavid Howells bool "Sign modules with SHA-512" 1630ea0b6dcfSDavid Howells select CRYPTO_SHA512 1631ea0b6dcfSDavid Howells 1632ea0b6dcfSDavid Howellsendchoice 1633ea0b6dcfSDavid Howells 16340b0de144SRobert P. J. Dayendif # MODULES 16350b0de144SRobert P. J. Day 163698a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 163798a79d6aSRusty Russell bool 163898a79d6aSRusty Russell help 16395f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 16405f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 164198a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 164298a79d6aSRusty Russell it was better to provide this option than to break all the archs 1643692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 164498a79d6aSRusty Russell 16451da177e4SLinus Torvaldsconfig STOP_MACHINE 16461da177e4SLinus Torvalds bool 16471da177e4SLinus Torvalds default y 16481da177e4SLinus Torvalds depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 16491da177e4SLinus Torvalds help 16501da177e4SLinus Torvalds Need stop_machine() primitive. 16513a65dfe8SJens Axboe 16523a65dfe8SJens Axboesource "block/Kconfig" 1653e98c3202SAvi Kivity 1654e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 1655e98c3202SAvi Kivity bool 1656e260be67SPaul E. McKenney 165716295becSSteffen Klassertconfig PADATA 165816295becSSteffen Klassert depends on SMP 165916295becSSteffen Klassert bool 166016295becSSteffen Klassert 1661754b7b63SAndi Kleen# Can be selected by architectures with broken toolchains 1662754b7b63SAndi Kleen# that get confused by correct const<->read_only section 1663754b7b63SAndi Kleen# mappings 1664754b7b63SAndi Kleenconfig BROKEN_RODATA 1665754b7b63SAndi Kleen bool 1666754b7b63SAndi Kleen 16674520c6a4SDavid Howellsconfig ASN1 16684520c6a4SDavid Howells tristate 16694520c6a4SDavid Howells help 16704520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 16714520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 16724520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 16734520c6a4SDavid Howells functions to call on what tags. 16744520c6a4SDavid Howells 16756beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 1676