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 325a958db3SKees Cook bool 335a958db3SKees Cook default y 341da177e4SLinus Torvalds 351da177e4SLinus Torvaldsconfig BROKEN 361da177e4SLinus Torvalds bool 371da177e4SLinus Torvalds 381da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 391da177e4SLinus Torvalds bool 401da177e4SLinus Torvalds depends on BROKEN || !SMP 411da177e4SLinus Torvalds default y 421da177e4SLinus Torvalds 431da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 441da177e4SLinus Torvalds int 45dd673bcaSAdrian Bunk default 32 if !UML 46dd673bcaSAdrian Bunk default 128 if UML 471da177e4SLinus Torvalds help 4834ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 4934ad92c2SRandy Dunlap variables passed to init from the kernel command line. 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds 5284336466SRoland McGrathconfig CROSS_COMPILE 5384336466SRoland McGrath string "Cross-compiler tool prefix" 5484336466SRoland McGrath help 5584336466SRoland McGrath Same as running 'make CROSS_COMPILE=prefix-' but stored for 5684336466SRoland McGrath default make runs in this kernel build directory. You don't 5784336466SRoland McGrath need to set this unless you want the configured kernel build 5884336466SRoland McGrath directory to select the cross-compiler automatically. 5984336466SRoland McGrath 601da177e4SLinus Torvaldsconfig LOCALVERSION 611da177e4SLinus Torvalds string "Local version - append to kernel release" 621da177e4SLinus Torvalds help 631da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 641da177e4SLinus Torvalds This will show up when you type uname, for example. 651da177e4SLinus Torvalds The string you set here will be appended after the contents of 661da177e4SLinus Torvalds any files with a filename matching localversion* in your 671da177e4SLinus Torvalds object and source tree, in that order. Your total string can 681da177e4SLinus Torvalds be a maximum of 64 characters. 691da177e4SLinus Torvalds 70aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 71aaebf433SRyan Anderson bool "Automatically append version information to the version string" 72aaebf433SRyan Anderson default y 73aaebf433SRyan Anderson help 74aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 756e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 766e5a5420SRobert P. J. Day top of tree revision. 77aaebf433SRyan Anderson 78aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 796e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 80aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 816e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 82aaebf433SRyan Anderson 836e5a5420SRobert P. J. Day (The actual string used here is the first eight characters produced 846e5a5420SRobert P. J. Day by running the command: 856e5a5420SRobert P. J. Day 866e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 876e5a5420SRobert P. J. Day 886e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 89aaebf433SRyan Anderson 902e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 912e9f3bddSH. Peter Anvin bool 922e9f3bddSH. Peter Anvin 932e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 942e9f3bddSH. Peter Anvin bool 952e9f3bddSH. Peter Anvin 962e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 972e9f3bddSH. Peter Anvin bool 982e9f3bddSH. Peter Anvin 993ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 1003ebe1243SLasse Collin bool 1013ebe1243SLasse Collin 1027dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 1037dd65febSAlbin Tonnerre bool 1047dd65febSAlbin Tonnerre 10530d65dbfSAlain Knaffchoice 10630d65dbfSAlain Knaff prompt "Kernel compression mode" 10730d65dbfSAlain Knaff default KERNEL_GZIP 1083ebe1243SLasse Collin depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO 10930d65dbfSAlain Knaff help 11030d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 11130d65dbfSAlain Knaff Several compression algorithms are available, which differ 11230d65dbfSAlain Knaff in efficiency, compression and decompression speed. 11330d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 11430d65dbfSAlain Knaff Decompression speed is relevant at each boot. 11530d65dbfSAlain Knaff 11630d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 11730d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 11830d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 11930d65dbfSAlain Knaff supplied by Christian Ludwig) 12030d65dbfSAlain Knaff 12130d65dbfSAlain Knaff High compression options are mostly useful for users, who 12230d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 12330d65dbfSAlain Knaff size matters less. 12430d65dbfSAlain Knaff 12530d65dbfSAlain Knaff If in doubt, select 'gzip' 12630d65dbfSAlain Knaff 12730d65dbfSAlain Knaffconfig KERNEL_GZIP 12830d65dbfSAlain Knaff bool "Gzip" 1292e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 13030d65dbfSAlain Knaff help 1317dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 1327dd65febSAlbin Tonnerre between compression ratio and decompression speed. 13330d65dbfSAlain Knaff 13430d65dbfSAlain Knaffconfig KERNEL_BZIP2 13530d65dbfSAlain Knaff bool "Bzip2" 1362e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 13730d65dbfSAlain Knaff help 13830d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 1390a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 1402e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 1412e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 1422e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 14330d65dbfSAlain Knaff 14430d65dbfSAlain Knaffconfig KERNEL_LZMA 14530d65dbfSAlain Knaff bool "LZMA" 1462e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 14730d65dbfSAlain Knaff help 1480a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 1490a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 1500a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 15130d65dbfSAlain Knaff 1523ebe1243SLasse Collinconfig KERNEL_XZ 1533ebe1243SLasse Collin bool "XZ" 1543ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 1553ebe1243SLasse Collin help 1563ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 1573ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 1583ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 1593ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 1603ebe1243SLasse Collin filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ 1613ebe1243SLasse Collin will create a few percent smaller kernel than plain LZMA. 1623ebe1243SLasse Collin 1633ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 1643ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 1653ebe1243SLasse Collin and LZO. Compression is slow. 1663ebe1243SLasse Collin 1677dd65febSAlbin Tonnerreconfig KERNEL_LZO 1687dd65febSAlbin Tonnerre bool "LZO" 1697dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 1707dd65febSAlbin Tonnerre help 1710a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 172681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 1737dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 1747dd65febSAlbin Tonnerre 17530d65dbfSAlain Knaffendchoice 17630d65dbfSAlain Knaff 177bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 178bd5dc17bSJosh Triplett string "Default hostname" 179bd5dc17bSJosh Triplett default "(none)" 180bd5dc17bSJosh Triplett help 181bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 182bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 183bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 184bd5dc17bSJosh Triplett system more usable with less configuration. 185bd5dc17bSJosh Triplett 1861da177e4SLinus Torvaldsconfig SWAP 1871da177e4SLinus Torvalds bool "Support for paging of anonymous memory (swap)" 1889361401eSDavid Howells depends on MMU && BLOCK 1891da177e4SLinus Torvalds default y 1901da177e4SLinus Torvalds help 1911da177e4SLinus Torvalds This option allows you to choose whether you want to have support 1921da177e4SLinus Torvalds for so called swap devices or swap files in your kernel that are 1931da177e4SLinus Torvalds used to provide more virtual memory than the actual RAM present 1941da177e4SLinus Torvalds in your computer. If unsure say Y. 1951da177e4SLinus Torvalds 1961da177e4SLinus Torvaldsconfig SYSVIPC 1971da177e4SLinus Torvalds bool "System V IPC" 1981da177e4SLinus Torvalds ---help--- 1991da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 2001da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 2011da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 2021da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 2031da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 2041da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 2051da177e4SLinus Torvalds you'll need to say Y here. 2061da177e4SLinus Torvalds 2071da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 2081da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 2091da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 2101da177e4SLinus Torvalds 211a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 212a5494dcdSEric W. Biederman bool 213a5494dcdSEric W. Biederman depends on SYSVIPC 214a5494dcdSEric W. Biederman depends on SYSCTL 215a5494dcdSEric W. Biederman default y 216a5494dcdSEric W. Biederman 2171da177e4SLinus Torvaldsconfig POSIX_MQUEUE 2181da177e4SLinus Torvalds bool "POSIX Message Queues" 21919c92399SKees Cook depends on NET 2201da177e4SLinus Torvalds ---help--- 2211da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 2221da177e4SLinus Torvalds queues every message has a priority which decides about succession 2231da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 2241da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 225b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 2281da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 2291da177e4SLinus Torvalds operations on message queues. 2301da177e4SLinus Torvalds 2311da177e4SLinus Torvalds If unsure, say Y. 2321da177e4SLinus Torvalds 233bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 234bdc8e5f8SSerge E. Hallyn bool 235bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 236bdc8e5f8SSerge E. Hallyn depends on SYSCTL 237bdc8e5f8SSerge E. Hallyn default y 238bdc8e5f8SSerge E. Hallyn 239990d6c2dSAneesh Kumar K.Vconfig FHANDLE 240990d6c2dSAneesh Kumar K.V bool "open by fhandle syscalls" 241990d6c2dSAneesh Kumar K.V select EXPORTFS 242990d6c2dSAneesh Kumar K.V help 243990d6c2dSAneesh Kumar K.V If you say Y here, a user level program will be able to map 244990d6c2dSAneesh Kumar K.V file names to handle and then later use the handle for 245990d6c2dSAneesh Kumar K.V different file system operations. This is useful in implementing 246990d6c2dSAneesh Kumar K.V userspace file servers, which now track files using handles instead 247990d6c2dSAneesh Kumar K.V of names. The handle would remain the same even if file names 248990d6c2dSAneesh Kumar K.V get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 249990d6c2dSAneesh Kumar K.V syscalls. 250990d6c2dSAneesh Kumar K.V 2511da177e4SLinus Torvaldsconfig AUDIT 2521da177e4SLinus Torvalds bool "Auditing support" 253804a6a49SChris Wright depends on NET 2541da177e4SLinus Torvalds help 2551da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 2561da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 2571da177e4SLinus Torvalds logging of avc messages output). Does not do system-call 2581da177e4SLinus Torvalds auditing without CONFIG_AUDITSYSCALL. 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvaldsconfig AUDITSYSCALL 2611da177e4SLinus Torvalds bool "Enable system-call auditing support" 2628f827a14SWill Deacon depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) 2631da177e4SLinus Torvalds default y if SECURITY_SELINUX 2641da177e4SLinus Torvalds help 2651da177e4SLinus Torvalds Enable low-overhead system-call auditing infrastructure that 2661da177e4SLinus Torvalds can be used independently or with another kernel subsystem, 26767640b60SEric Paris such as SELinux. 2681da177e4SLinus Torvalds 269939a67fcSEric Parisconfig AUDIT_WATCH 270939a67fcSEric Paris def_bool y 271939a67fcSEric Paris depends on AUDITSYSCALL 272939a67fcSEric Paris select FSNOTIFY 2731da177e4SLinus Torvalds 27474c3cbe3SAl Viroconfig AUDIT_TREE 27574c3cbe3SAl Viro def_bool y 27663c882a0SEric Paris depends on AUDITSYSCALL 27728a3a7ebSEric Paris select FSNOTIFY 27874c3cbe3SAl Viro 279633b4545SEric Parisconfig AUDIT_LOGINUID_IMMUTABLE 280633b4545SEric Paris bool "Make audit loginuid immutable" 281633b4545SEric Paris depends on AUDIT 282633b4545SEric Paris help 283f429ee3bSLinus Torvalds The config option toggles if a task setting its loginuid requires 284633b4545SEric Paris CAP_SYS_AUDITCONTROL or if that task should require no special permissions 285633b4545SEric Paris but should instead only allow setting its loginuid if it was never 286633b4545SEric Paris previously set. On systems which use systemd or a similar central 287633b4545SEric Paris process to restart login services this should be set to true. On older 288633b4545SEric Paris systems in which an admin would typically have to directly stop and 289633b4545SEric Paris start processes this should be set to false. Setting this to true allows 290633b4545SEric Paris one to drop potentially dangerous capabilites from the login tasks, 291633b4545SEric Paris but may not be backwards compatible with older init systems. 292633b4545SEric Paris 293d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 294764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 295d9817ebeSThomas Gleixner 296391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 297391dc69cSFrederic Weisbecker 298abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 299abf917cdSFrederic Weisbecker bool 300abf917cdSFrederic Weisbecker 301fdf9c356SFrederic Weisbeckerchoice 302fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 303fdf9c356SFrederic Weisbecker default TICK_CPU_ACCOUNTING if !PPC64 30402fc8d37SStephen Rothwell default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 305fdf9c356SFrederic Weisbecker 306fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 307fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 308fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 309fdf9c356SFrederic Weisbecker depends on !S390 310fdf9c356SFrederic Weisbecker help 311fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 312fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 313fdf9c356SFrederic Weisbecker granularity. 314fdf9c356SFrederic Weisbecker 315fdf9c356SFrederic Weisbecker If unsure, say Y. 316fdf9c356SFrederic Weisbecker 317abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE 318391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 319391dc69cSFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING 320abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 321391dc69cSFrederic Weisbecker help 322391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 323391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 324391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 325391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 326391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 327391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 328391dc69cSFrederic Weisbecker systems. 329391dc69cSFrederic Weisbecker 330abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN 331abf917cdSFrederic Weisbecker bool "Full dynticks CPU time accounting" 332abf917cdSFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING && 64BIT 333abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 334abf917cdSFrederic Weisbecker select CONTEXT_TRACKING 335abf917cdSFrederic Weisbecker help 336abf917cdSFrederic Weisbecker Select this option to enable task and CPU time accounting on full 337abf917cdSFrederic Weisbecker dynticks systems. This accounting is implemented by watching every 338abf917cdSFrederic Weisbecker kernel-user boundaries using the context tracking subsystem. 339abf917cdSFrederic Weisbecker The accounting is thus performed at the expense of some significant 340abf917cdSFrederic Weisbecker overhead. 341abf917cdSFrederic Weisbecker 342abf917cdSFrederic Weisbecker For now this is only useful if you are working on the full 343abf917cdSFrederic Weisbecker dynticks subsystem development. 344abf917cdSFrederic Weisbecker 345abf917cdSFrederic Weisbecker If unsure, say N. 346abf917cdSFrederic Weisbecker 347fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 348fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 349fdf9c356SFrederic Weisbecker depends on HAVE_IRQ_TIME_ACCOUNTING 350fdf9c356SFrederic Weisbecker help 351fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 352fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 353fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 354fdf9c356SFrederic Weisbecker small performance impact. 355fdf9c356SFrederic Weisbecker 356fdf9c356SFrederic Weisbecker If in doubt, say N here. 357fdf9c356SFrederic Weisbecker 358fdf9c356SFrederic Weisbeckerendchoice 359fdf9c356SFrederic Weisbecker 360391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 361391dc69cSFrederic Weisbecker bool "BSD Process Accounting" 362391dc69cSFrederic Weisbecker help 363391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 364391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 365391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 366391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 367391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 368391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 369391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 370391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 371391dc69cSFrederic Weisbecker information. This is generally a good idea, so say Y. 372391dc69cSFrederic Weisbecker 373391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 374391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 375391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 376391dc69cSFrederic Weisbecker default n 377391dc69cSFrederic Weisbecker help 378391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 379391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 380391dc69cSFrederic Weisbecker process and it's parent. Note that this file format is incompatible 381391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 382391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 383391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 384391dc69cSFrederic Weisbecker 385391dc69cSFrederic Weisbeckerconfig TASKSTATS 38619c92399SKees Cook bool "Export task/process statistics through netlink" 387391dc69cSFrederic Weisbecker depends on NET 388391dc69cSFrederic Weisbecker default n 389391dc69cSFrederic Weisbecker help 390391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 391391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 392391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 393391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 394391dc69cSFrederic Weisbecker space on task exit. 395391dc69cSFrederic Weisbecker 396391dc69cSFrederic Weisbecker Say N if unsure. 397391dc69cSFrederic Weisbecker 398391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 39919c92399SKees Cook bool "Enable per-task delay accounting" 400391dc69cSFrederic Weisbecker depends on TASKSTATS 401391dc69cSFrederic Weisbecker help 402391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 403391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 404391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 405391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 406391dc69cSFrederic Weisbecker 407391dc69cSFrederic Weisbecker Say N if unsure. 408391dc69cSFrederic Weisbecker 409391dc69cSFrederic Weisbeckerconfig TASK_XACCT 41019c92399SKees Cook bool "Enable extended accounting over taskstats" 411391dc69cSFrederic Weisbecker depends on TASKSTATS 412391dc69cSFrederic Weisbecker help 413391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 414391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 415391dc69cSFrederic Weisbecker 416391dc69cSFrederic Weisbecker Say N if unsure. 417391dc69cSFrederic Weisbecker 418391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 41919c92399SKees Cook bool "Enable per-task storage I/O accounting" 420391dc69cSFrederic Weisbecker depends on TASK_XACCT 421391dc69cSFrederic Weisbecker help 422391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 423391dc69cSFrederic Weisbecker task has caused. 424391dc69cSFrederic Weisbecker 425391dc69cSFrederic Weisbecker Say N if unsure. 426391dc69cSFrederic Weisbecker 427391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 428391dc69cSFrederic Weisbecker 429c903ff83SMike Travismenu "RCU Subsystem" 430c903ff83SMike Travis 431c903ff83SMike Travischoice 432c903ff83SMike Travis prompt "RCU Implementation" 43331c9a24eSPaul E. McKenney default TREE_RCU 434c903ff83SMike Travis 435c903ff83SMike Travisconfig TREE_RCU 436c903ff83SMike Travis bool "Tree-based hierarchical RCU" 437687d7a96SPaul E. McKenney depends on !PREEMPT && SMP 438c903ff83SMike Travis help 439c903ff83SMike Travis This option selects the RCU implementation that is 440c903ff83SMike Travis designed for very large SMP system with hundreds or 441c17ef453SPaul E. McKenney thousands of CPUs. It also scales down nicely to 442c17ef453SPaul E. McKenney smaller systems. 443c903ff83SMike Travis 444f41d911fSPaul E. McKenneyconfig TREE_PREEMPT_RCU 445a57eb940SPaul E. McKenney bool "Preemptible tree-based hierarchical RCU" 4469fc52d83SPaul E. McKenney depends on PREEMPT 447f41d911fSPaul E. McKenney help 448f41d911fSPaul E. McKenney This option selects the RCU implementation that is 449f41d911fSPaul E. McKenney designed for very large SMP systems with hundreds or 450f41d911fSPaul E. McKenney thousands of CPUs, but for which real-time response 451bbe3eae8SPaul E. McKenney is also required. It also scales down nicely to 452bbe3eae8SPaul E. McKenney smaller systems. 453f41d911fSPaul E. McKenney 4549fc52d83SPaul E. McKenney Select this option if you are unsure. 4559fc52d83SPaul E. McKenney 4569b1d82faSPaul E. McKenneyconfig TINY_RCU 4579b1d82faSPaul E. McKenney bool "UP-only small-memory-footprint RCU" 4588008e129SPaul E. McKenney depends on !PREEMPT && !SMP 4599b1d82faSPaul E. McKenney help 4609b1d82faSPaul E. McKenney This option selects the RCU implementation that is 4619b1d82faSPaul E. McKenney designed for UP systems from which real-time response 4629b1d82faSPaul E. McKenney is not required. This option greatly reduces the 4639b1d82faSPaul E. McKenney memory footprint of RCU. 4649b1d82faSPaul E. McKenney 465a57eb940SPaul E. McKenneyconfig TINY_PREEMPT_RCU 466a57eb940SPaul E. McKenney bool "Preemptible UP-only small-memory-footprint RCU" 4678008e129SPaul E. McKenney depends on PREEMPT && !SMP 468a57eb940SPaul E. McKenney help 469a57eb940SPaul E. McKenney This option selects the RCU implementation that is designed 470a57eb940SPaul E. McKenney for real-time UP systems. This option greatly reduces the 471a57eb940SPaul E. McKenney memory footprint of RCU. 472a57eb940SPaul E. McKenney 473c903ff83SMike Travisendchoice 474c903ff83SMike Travis 475a57eb940SPaul E. McKenneyconfig PREEMPT_RCU 476a57eb940SPaul E. McKenney def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) 477a57eb940SPaul E. McKenney help 478a57eb940SPaul E. McKenney This option enables preemptible-RCU code that is common between 479a57eb940SPaul E. McKenney the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. 480a57eb940SPaul E. McKenney 4816bfc09e2SPaul E. McKenneyconfig RCU_STALL_COMMON 4826bfc09e2SPaul E. McKenney def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE ) 4836bfc09e2SPaul E. McKenney help 4846bfc09e2SPaul E. McKenney This option enables RCU CPU stall code that is common between 4856bfc09e2SPaul E. McKenney the TINY and TREE variants of RCU. The purpose is to allow 4866bfc09e2SPaul E. McKenney the tiny variants to disable RCU CPU stall warnings, while 4876bfc09e2SPaul E. McKenney making these warnings mandatory for the tree variants. 4886bfc09e2SPaul E. McKenney 48991d1aa43SFrederic Weisbeckerconfig CONTEXT_TRACKING 49091d1aa43SFrederic Weisbecker bool 49191d1aa43SFrederic Weisbecker 4922b1d5024SFrederic Weisbeckerconfig RCU_USER_QS 4932b1d5024SFrederic Weisbecker bool "Consider userspace as in RCU extended quiescent state" 49491d1aa43SFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING && SMP 49591d1aa43SFrederic Weisbecker select CONTEXT_TRACKING 4962b1d5024SFrederic Weisbecker help 4972b1d5024SFrederic Weisbecker This option sets hooks on kernel / userspace boundaries and 4982b1d5024SFrederic Weisbecker puts RCU in extended quiescent state when the CPU runs in 4992b1d5024SFrederic Weisbecker userspace. It means that when a CPU runs in userspace, it is 5002b1d5024SFrederic Weisbecker excluded from the global RCU state machine and thus doesn't 501af71befaSPaul Gortmaker try to keep the timer tick on for RCU. 5022b1d5024SFrederic Weisbecker 503d677124bSFrederic Weisbecker Unless you want to hack and help the development of the full 50491d1aa43SFrederic Weisbecker dynticks mode, you shouldn't enable this option. It also 505af71befaSPaul Gortmaker adds unnecessary overhead. 506d677124bSFrederic Weisbecker 507d677124bSFrederic Weisbecker If unsure say N 508d677124bSFrederic Weisbecker 50991d1aa43SFrederic Weisbeckerconfig CONTEXT_TRACKING_FORCE 51091d1aa43SFrederic Weisbecker bool "Force context tracking" 51191d1aa43SFrederic Weisbecker depends on CONTEXT_TRACKING 512*8b438766SFrederic Weisbecker default CONTEXT_TRACKING 5131fd2b442SFrederic Weisbecker help 51491d1aa43SFrederic Weisbecker Probe on user/kernel boundaries by default in order to 51591d1aa43SFrederic Weisbecker test the features that rely on it such as userspace RCU extended 51691d1aa43SFrederic Weisbecker quiescent states. 51791d1aa43SFrederic Weisbecker This test is there for debugging until we have a real user like the 51891d1aa43SFrederic Weisbecker full dynticks mode. 519d677124bSFrederic Weisbecker 520c903ff83SMike Travisconfig RCU_FANOUT 521c903ff83SMike Travis int "Tree-based hierarchical RCU fanout value" 522c903ff83SMike Travis range 2 64 if 64BIT 523c903ff83SMike Travis range 2 32 if !64BIT 524f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 525c903ff83SMike Travis default 64 if 64BIT 526c903ff83SMike Travis default 32 if !64BIT 527c903ff83SMike Travis help 528c903ff83SMike Travis This option controls the fanout of hierarchical implementations 529c903ff83SMike Travis of RCU, allowing RCU to work efficiently on machines with 5304d87ffadSPaul E. McKenney large numbers of CPUs. This value must be at least the fourth 5314d87ffadSPaul E. McKenney root of NR_CPUS, which allows NR_CPUS to be insanely large. 5324d87ffadSPaul E. McKenney The default value of RCU_FANOUT should be used for production 5334d87ffadSPaul E. McKenney systems, but if you are stress-testing the RCU implementation 5344d87ffadSPaul E. McKenney itself, small RCU_FANOUT values allow you to test large-system 5354d87ffadSPaul E. McKenney code paths on small(er) systems. 536c903ff83SMike Travis 537c903ff83SMike Travis Select a specific number if testing RCU itself. 538c903ff83SMike Travis Take the default if unsure. 539c903ff83SMike Travis 5408932a63dSPaul E. McKenneyconfig RCU_FANOUT_LEAF 5418932a63dSPaul E. McKenney int "Tree-based hierarchical RCU leaf-level fanout value" 5428932a63dSPaul E. McKenney range 2 RCU_FANOUT if 64BIT 5438932a63dSPaul E. McKenney range 2 RCU_FANOUT if !64BIT 5448932a63dSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 5458932a63dSPaul E. McKenney default 16 5468932a63dSPaul E. McKenney help 5478932a63dSPaul E. McKenney This option controls the leaf-level fanout of hierarchical 5488932a63dSPaul E. McKenney implementations of RCU, and allows trading off cache misses 5498932a63dSPaul E. McKenney against lock contention. Systems that synchronize their 5508932a63dSPaul E. McKenney scheduling-clock interrupts for energy-efficiency reasons will 5518932a63dSPaul E. McKenney want the default because the smaller leaf-level fanout keeps 5528932a63dSPaul E. McKenney lock contention levels acceptably low. Very large systems 5538932a63dSPaul E. McKenney (hundreds or thousands of CPUs) will instead want to set this 5548932a63dSPaul E. McKenney value to the maximum value possible in order to reduce the 5558932a63dSPaul E. McKenney number of cache misses incurred during RCU's grace-period 5568932a63dSPaul E. McKenney initialization. These systems tend to run CPU-bound, and thus 5578932a63dSPaul E. McKenney are not helped by synchronized interrupts, and thus tend to 5588932a63dSPaul E. McKenney skew them, which reduces lock contention enough that large 5598932a63dSPaul E. McKenney leaf-level fanouts work well. 5608932a63dSPaul E. McKenney 5618932a63dSPaul E. McKenney Select a specific number if testing RCU itself. 5628932a63dSPaul E. McKenney 5638932a63dSPaul E. McKenney Select the maximum permissible value for large systems. 5648932a63dSPaul E. McKenney 5658932a63dSPaul E. McKenney Take the default if unsure. 5668932a63dSPaul E. McKenney 567c903ff83SMike Travisconfig RCU_FANOUT_EXACT 568c903ff83SMike Travis bool "Disable tree-based hierarchical RCU auto-balancing" 569f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 570c903ff83SMike Travis default n 571c903ff83SMike Travis help 572c903ff83SMike Travis This option forces use of the exact RCU_FANOUT value specified, 573c903ff83SMike Travis regardless of imbalances in the hierarchy. This is useful for 574c903ff83SMike Travis testing RCU itself, and might one day be useful on systems with 575c903ff83SMike Travis strong NUMA behavior. 576c903ff83SMike Travis 577c903ff83SMike Travis Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 578c903ff83SMike Travis 579c903ff83SMike Travis Say N if unsure. 580c903ff83SMike Travis 5818bd93a2cSPaul E. McKenneyconfig RCU_FAST_NO_HZ 5828bd93a2cSPaul E. McKenney bool "Accelerate last non-dyntick-idle CPU's grace periods" 583b807fbffSPaul E. McKenney depends on NO_HZ && SMP 5848bd93a2cSPaul E. McKenney default n 5858bd93a2cSPaul E. McKenney help 586ba49df47SPaul E. McKenney This option causes RCU to attempt to accelerate grace periods in 587ba49df47SPaul E. McKenney order to allow CPUs to enter dynticks-idle state more quickly. 588ba49df47SPaul E. McKenney On the other hand, this option increases the overhead of the 589ba49df47SPaul E. McKenney dynticks-idle checking, thus degrading scheduling latency. 5908bd93a2cSPaul E. McKenney 591ba49df47SPaul E. McKenney Say Y if energy efficiency is critically important, and you don't 592ba49df47SPaul E. McKenney care about real-time response. 5938bd93a2cSPaul E. McKenney 5948bd93a2cSPaul E. McKenney Say N if you are unsure. 5958bd93a2cSPaul E. McKenney 596c903ff83SMike Travisconfig TREE_RCU_TRACE 597f41d911fSPaul E. McKenney def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) 598c903ff83SMike Travis select DEBUG_FS 599c903ff83SMike Travis help 600f41d911fSPaul E. McKenney This option provides tracing for the TREE_RCU and 601f41d911fSPaul E. McKenney TREE_PREEMPT_RCU implementations, permitting Makefile to 602f41d911fSPaul E. McKenney trivially select kernel/rcutree_trace.c. 603c903ff83SMike Travis 60424278d14SPaul E. McKenneyconfig RCU_BOOST 60524278d14SPaul E. McKenney bool "Enable RCU priority boosting" 60627f4d280SPaul E. McKenney depends on RT_MUTEXES && PREEMPT_RCU 60724278d14SPaul E. McKenney default n 60824278d14SPaul E. McKenney help 60924278d14SPaul E. McKenney This option boosts the priority of preempted RCU readers that 61024278d14SPaul E. McKenney block the current preemptible RCU grace period for too long. 61124278d14SPaul E. McKenney This option also prevents heavy loads from blocking RCU 61224278d14SPaul E. McKenney callback invocation for all flavors of RCU. 61324278d14SPaul E. McKenney 61424278d14SPaul E. McKenney Say Y here if you are working with real-time apps or heavy loads 61524278d14SPaul E. McKenney Say N here if you are unsure. 61624278d14SPaul E. McKenney 61724278d14SPaul E. McKenneyconfig RCU_BOOST_PRIO 61824278d14SPaul E. McKenney int "Real-time priority to boost RCU readers to" 61924278d14SPaul E. McKenney range 1 99 62024278d14SPaul E. McKenney depends on RCU_BOOST 62124278d14SPaul E. McKenney default 1 62224278d14SPaul E. McKenney help 623c9336643SPaul E. McKenney This option specifies the real-time priority to which long-term 624c9336643SPaul E. McKenney preempted RCU readers are to be boosted. If you are working 625c9336643SPaul E. McKenney with a real-time application that has one or more CPU-bound 626c9336643SPaul E. McKenney threads running at a real-time priority level, you should set 627c9336643SPaul E. McKenney RCU_BOOST_PRIO to a priority higher then the highest-priority 628c9336643SPaul E. McKenney real-time CPU-bound thread. The default RCU_BOOST_PRIO value 629c9336643SPaul E. McKenney of 1 is appropriate in the common case, which is real-time 630c9336643SPaul E. McKenney applications that do not have any CPU-bound threads. 631c9336643SPaul E. McKenney 632c9336643SPaul E. McKenney Some real-time applications might not have a single real-time 633c9336643SPaul E. McKenney thread that saturates a given CPU, but instead might have 634c9336643SPaul E. McKenney multiple real-time threads that, taken together, fully utilize 635c9336643SPaul E. McKenney that CPU. In this case, you should set RCU_BOOST_PRIO to 636c9336643SPaul E. McKenney a priority higher than the lowest-priority thread that is 637c9336643SPaul E. McKenney conspiring to prevent the CPU from running any non-real-time 638c9336643SPaul E. McKenney tasks. For example, if one thread at priority 10 and another 639c9336643SPaul E. McKenney thread at priority 5 are between themselves fully consuming 640c9336643SPaul E. McKenney the CPU time on a given CPU, then RCU_BOOST_PRIO should be 641c9336643SPaul E. McKenney set to priority 6 or higher. 64224278d14SPaul E. McKenney 64324278d14SPaul E. McKenney Specify the real-time priority, or take the default if unsure. 64424278d14SPaul E. McKenney 64524278d14SPaul E. McKenneyconfig RCU_BOOST_DELAY 64624278d14SPaul E. McKenney int "Milliseconds to delay boosting after RCU grace-period start" 64724278d14SPaul E. McKenney range 0 3000 64824278d14SPaul E. McKenney depends on RCU_BOOST 64924278d14SPaul E. McKenney default 500 65024278d14SPaul E. McKenney help 65124278d14SPaul E. McKenney This option specifies the time to wait after the beginning of 65224278d14SPaul E. McKenney a given grace period before priority-boosting preempted RCU 65324278d14SPaul E. McKenney readers blocking that grace period. Note that any RCU reader 65424278d14SPaul E. McKenney blocking an expedited RCU grace period is boosted immediately. 65524278d14SPaul E. McKenney 65624278d14SPaul E. McKenney Accept the default if unsure. 65724278d14SPaul E. McKenney 6583fbfbf7aSPaul E. McKenneyconfig RCU_NOCB_CPU 6593fbfbf7aSPaul E. McKenney bool "Offload RCU callback processing from boot-selected CPUs" 6603fbfbf7aSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 6613fbfbf7aSPaul E. McKenney default n 6623fbfbf7aSPaul E. McKenney help 6633fbfbf7aSPaul E. McKenney Use this option to reduce OS jitter for aggressive HPC or 6643fbfbf7aSPaul E. McKenney real-time workloads. It can also be used to offload RCU 6653fbfbf7aSPaul E. McKenney callback invocation to energy-efficient CPUs in battery-powered 6663fbfbf7aSPaul E. McKenney asymmetric multiprocessors. 6673fbfbf7aSPaul E. McKenney 6683fbfbf7aSPaul E. McKenney This option offloads callback invocation from the set of 6693fbfbf7aSPaul E. McKenney CPUs specified at boot time by the rcu_nocbs parameter. 6703fbfbf7aSPaul E. McKenney For each such CPU, a kthread ("rcuoN") will be created to 6713fbfbf7aSPaul E. McKenney invoke callbacks, where the "N" is the CPU being offloaded. 6723fbfbf7aSPaul E. McKenney Nothing prevents this kthread from running on the specified 6733fbfbf7aSPaul E. McKenney CPUs, but (1) the kthreads may be preempted between each 6743fbfbf7aSPaul E. McKenney callback, and (2) affinity or cgroups can be used to force 6753fbfbf7aSPaul E. McKenney the kthreads to run on whatever set of CPUs is desired. 6763fbfbf7aSPaul E. McKenney 6773fbfbf7aSPaul E. McKenney Say Y here if you want reduced OS jitter on selected CPUs. 6783fbfbf7aSPaul E. McKenney Say N here if you are unsure. 6793fbfbf7aSPaul E. McKenney 680c903ff83SMike Travisendmenu # "RCU Subsystem" 681c903ff83SMike Travis 6821da177e4SLinus Torvaldsconfig IKCONFIG 683f2443ab6SRoss Biro tristate "Kernel .config support" 6841da177e4SLinus Torvalds ---help--- 6851da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 6861da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 6871da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 6881da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 6891da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 6901da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 6911da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 6921da177e4SLinus Torvalds /proc/config.gz if enabled (below). 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvaldsconfig IKCONFIG_PROC 6951da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 6961da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 6971da177e4SLinus Torvalds ---help--- 6981da177e4SLinus Torvalds This option enables access to the kernel configuration file 6991da177e4SLinus Torvalds through /proc/config.gz. 7001da177e4SLinus Torvalds 701794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 702794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 703794543a2SAlistair John Strachan range 12 21 704f17a32e9SAdrian Bunk default 17 705794543a2SAlistair John Strachan help 706794543a2SAlistair John Strachan Select kernel log buffer size as a power of 2. 707f17a32e9SAdrian Bunk Examples: 708f17a32e9SAdrian Bunk 17 => 128 KB 709f17a32e9SAdrian Bunk 16 => 64 KB 710f17a32e9SAdrian Bunk 15 => 32 KB 711f17a32e9SAdrian Bunk 14 => 16 KB 712794543a2SAlistair John Strachan 13 => 8 KB 713794543a2SAlistair John Strachan 12 => 4 KB 714794543a2SAlistair John Strachan 7155cdc38f9SKAMEZAWA Hiroyuki# 7165cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 7175cdc38f9SKAMEZAWA Hiroyuki# 7185cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 7195cdc38f9SKAMEZAWA Hiroyuki bool 7205cdc38f9SKAMEZAWA Hiroyuki 721be3a7284SAndrea Arcangeli# 722be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler 723be3a7284SAndrea Arcangeli# balancing logic: 724be3a7284SAndrea Arcangeli# 725be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING 726be3a7284SAndrea Arcangeli bool 727be3a7284SAndrea Arcangeli 728be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions 729be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH. 730be3a7284SAndrea Arcangeli# 731be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY 732be3a7284SAndrea Arcangeli bool 733be3a7284SAndrea Arcangeli 734be3a7284SAndrea Arcangeli# 735be3a7284SAndrea Arcangeli# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE 736be3a7284SAndrea Arcangeliconfig ARCH_WANTS_PROT_NUMA_PROT_NONE 737be3a7284SAndrea Arcangeli bool 738be3a7284SAndrea Arcangeli 739be3a7284SAndrea Arcangeliconfig ARCH_USES_NUMA_PROT_NONE 740be3a7284SAndrea Arcangeli bool 741be3a7284SAndrea Arcangeli default y 742be3a7284SAndrea Arcangeli depends on ARCH_WANTS_PROT_NUMA_PROT_NONE 743be3a7284SAndrea Arcangeli depends on NUMA_BALANCING 744be3a7284SAndrea Arcangeli 7451a687c2eSMel Gormanconfig NUMA_BALANCING_DEFAULT_ENABLED 7461a687c2eSMel Gorman bool "Automatically enable NUMA aware memory/task placement" 7471a687c2eSMel Gorman default y 7481a687c2eSMel Gorman depends on NUMA_BALANCING 7491a687c2eSMel Gorman help 7501a687c2eSMel Gorman If set, autonumic NUMA balancing will be enabled if running on a NUMA 7511a687c2eSMel Gorman machine. 7521a687c2eSMel Gorman 753be3a7284SAndrea Arcangeliconfig NUMA_BALANCING 754be3a7284SAndrea Arcangeli bool "Memory placement aware NUMA scheduler" 755be3a7284SAndrea Arcangeli depends on ARCH_SUPPORTS_NUMA_BALANCING 756be3a7284SAndrea Arcangeli depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 757be3a7284SAndrea Arcangeli depends on SMP && NUMA && MIGRATION 758be3a7284SAndrea Arcangeli help 759be3a7284SAndrea Arcangeli This option adds support for automatic NUMA aware memory/task placement. 760be3a7284SAndrea Arcangeli The mechanism is quite primitive and is based on migrating memory when 761be3a7284SAndrea Arcangeli it is references to the node the task is running on. 762be3a7284SAndrea Arcangeli 763be3a7284SAndrea Arcangeli This system will be inactive on UMA systems. 764be3a7284SAndrea Arcangeli 76523964d2dSLi Zefanmenuconfig CGROUPS 76623964d2dSLi Zefan boolean "Control Group support" 7670dea1168SKirill A. Shutemov depends on EVENTFD 768ddbcc7e8SPaul Menage help 76923964d2dSLi Zefan This option adds support for grouping sets of processes together, for 7705cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 7715cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 7725cdc38f9SKAMEZAWA Hiroyuki See 7735cdc38f9SKAMEZAWA Hiroyuki - Documentation/scheduler/sched-design-CFS.txt (CFS) 77445ce80fbSLi Zefan - Documentation/cgroups/ (features for grouping, isolation 77545ce80fbSLi Zefan and resource control) 776ddbcc7e8SPaul Menage 777ddbcc7e8SPaul Menage Say N if unsure. 778ddbcc7e8SPaul Menage 77923964d2dSLi Zefanif CGROUPS 78023964d2dSLi Zefan 781006cb992SPaul Menageconfig CGROUP_DEBUG 782006cb992SPaul Menage bool "Example debug cgroup subsystem" 783418d7d87SPaul Menage default n 784006cb992SPaul Menage help 785006cb992SPaul Menage This option enables a simple cgroup subsystem that 786006cb992SPaul Menage exports useful debugging information about the cgroups 78723964d2dSLi Zefan framework. 788006cb992SPaul Menage 78923964d2dSLi Zefan Say N if unsure. 790006cb992SPaul Menage 791dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER 79223964d2dSLi Zefan bool "Freezer cgroup subsystem" 793dc52ddc0SMatt Helsley help 794dc52ddc0SMatt Helsley Provides a way to freeze and unfreeze all tasks in a 795dc52ddc0SMatt Helsley cgroup. 796dc52ddc0SMatt Helsley 79708ce5f16SSerge E. Hallynconfig CGROUP_DEVICE 79808ce5f16SSerge E. Hallyn bool "Device controller for cgroups" 79908ce5f16SSerge E. Hallyn help 80008ce5f16SSerge E. Hallyn Provides a cgroup implementing whitelists for devices which 80108ce5f16SSerge E. Hallyn a process in the cgroup can mknod or open. 80208ce5f16SSerge E. Hallyn 8031da177e4SLinus Torvaldsconfig CPUSETS 8041da177e4SLinus Torvalds bool "Cpuset support" 8051da177e4SLinus Torvalds help 806d9fd8a6dSRandy Dunlap This option will let you create and manage CPUSETs which 8071da177e4SLinus Torvalds allow dynamically partitioning a system into sets of CPUs and 8081da177e4SLinus Torvalds Memory Nodes and assigning tasks to run only within those sets. 8091da177e4SLinus Torvalds This is primarily useful on large SMP or NUMA systems. 8101da177e4SLinus Torvalds 8111da177e4SLinus Torvalds Say N if unsure. 8121da177e4SLinus Torvalds 81323964d2dSLi Zefanconfig PROC_PID_CPUSET 81423964d2dSLi Zefan bool "Include legacy /proc/<pid>/cpuset file" 81523964d2dSLi Zefan depends on CPUSETS 81623964d2dSLi Zefan default y 81723964d2dSLi Zefan 818d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT 819d842de87SSrivatsa Vaddagiri bool "Simple CPU accounting cgroup subsystem" 820d842de87SSrivatsa Vaddagiri help 821d842de87SSrivatsa Vaddagiri Provides a simple Resource Controller for monitoring the 82223964d2dSLi Zefan total CPU consumed by the tasks in a cgroup. 823d842de87SSrivatsa Vaddagiri 824e552b661SPavel Emelianovconfig RESOURCE_COUNTERS 825e552b661SPavel Emelianov bool "Resource counters" 826e552b661SPavel Emelianov help 827e552b661SPavel Emelianov This option enables controller independent resource accounting 82823964d2dSLi Zefan infrastructure that works with cgroups. 829e552b661SPavel Emelianov 830c255a458SAndrew Mortonconfig MEMCG 83100f0b825SBalbir Singh bool "Memory Resource Controller for Control Groups" 83279ae9c29SDaniel Lezcano depends on RESOURCE_COUNTERS 833cf475ad2SBalbir Singh select MM_OWNER 83400f0b825SBalbir Singh help 83584ad6d70SKAMEZAWA Hiroyuki Provides a memory resource controller that manages both anonymous 83621acb9caSThadeu Lima de Souza Cascardo memory and page cache. (See Documentation/cgroups/memory.txt) 83700f0b825SBalbir Singh 83800f0b825SBalbir Singh Note that setting this option increases fixed memory overhead 83984ad6d70SKAMEZAWA Hiroyuki associated with each page of memory in the system. By this, 84084ad6d70SKAMEZAWA Hiroyuki 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 84184ad6d70SKAMEZAWA Hiroyuki usage tracking struct at boot. Total amount of this is printed out 84284ad6d70SKAMEZAWA Hiroyuki at boot. 84300f0b825SBalbir Singh 84400f0b825SBalbir Singh Only enable when you're ok with these trade offs and really 84584ad6d70SKAMEZAWA Hiroyuki sure you need the memory resource controller. Even when you enable 84684ad6d70SKAMEZAWA Hiroyuki this, you can set "cgroup_disable=memory" at your boot option to 84784ad6d70SKAMEZAWA Hiroyuki disable memory resource controller and you can avoid overheads. 848c9d5409fSLi Zefan (and lose benefits of memory resource controller) 84900f0b825SBalbir Singh 850cf475ad2SBalbir Singh This config option also selects MM_OWNER config option, which 851cf475ad2SBalbir Singh could in turn add some fork/exit overhead. 852cf475ad2SBalbir Singh 853c255a458SAndrew Mortonconfig MEMCG_SWAP 85465e0e811SKAMEZAWA Hiroyuki bool "Memory Resource Controller Swap Extension" 855c255a458SAndrew Morton depends on MEMCG && SWAP 856c077719bSKAMEZAWA Hiroyuki help 857c077719bSKAMEZAWA Hiroyuki Add swap management feature to memory resource controller. When you 858c077719bSKAMEZAWA Hiroyuki enable this, you can limit mem+swap usage per cgroup. In other words, 859c077719bSKAMEZAWA Hiroyuki when you disable this, memory resource controller has no cares to 860c077719bSKAMEZAWA Hiroyuki usage of swap...a process can exhaust all of the swap. This extension 861c077719bSKAMEZAWA Hiroyuki is useful when you want to avoid exhaustion swap but this itself 862c077719bSKAMEZAWA Hiroyuki adds more overheads and consumes memory for remembering information. 863c077719bSKAMEZAWA Hiroyuki Especially if you use 32bit system or small memory system, please 864c077719bSKAMEZAWA Hiroyuki be careful about enabling this. When memory resource controller 865c077719bSKAMEZAWA Hiroyuki is disabled by boot option, this will be automatically disabled and 866c077719bSKAMEZAWA Hiroyuki there will be no overhead from this. Even when you set this config=y, 86700a66d29SWANG Cong if boot option "swapaccount=0" is set, swap will not be accounted. 868627991a2SKAMEZAWA Hiroyuki Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page 869627991a2SKAMEZAWA Hiroyuki size is 4096bytes, 512k per 1Gbytes of swap. 870c255a458SAndrew Mortonconfig MEMCG_SWAP_ENABLED 871a42c390cSMichal Hocko bool "Memory Resource Controller Swap Extension enabled by default" 872c255a458SAndrew Morton depends on MEMCG_SWAP 873a42c390cSMichal Hocko default y 874a42c390cSMichal Hocko help 875a42c390cSMichal Hocko Memory Resource Controller Swap Extension comes with its price in 876a42c390cSMichal Hocko a bigger memory consumption. General purpose distribution kernels 87743d547f9SJim Cromie which want to enable the feature but keep it disabled by default 878a42c390cSMichal Hocko and let the user enable it by swapaccount boot command line 879a42c390cSMichal Hocko parameter should have this option unselected. 880a42c390cSMichal Hocko For those who want to have the feature enabled by default should 881a42c390cSMichal Hocko select this option (if, for some reason, they need to disable it 88200a66d29SWANG Cong then swapaccount=0 does the trick). 883c255a458SAndrew Mortonconfig MEMCG_KMEM 88419c92399SKees Cook bool "Memory Resource Controller Kernel Memory accounting" 88519c92399SKees Cook depends on MEMCG 886510fc4e1SGlauber Costa depends on SLUB || SLAB 887e5671dfaSGlauber Costa help 888e5671dfaSGlauber Costa The Kernel Memory extension for Memory Resource Controller can limit 889e5671dfaSGlauber Costa the amount of memory used by kernel objects in the system. Those are 890e5671dfaSGlauber Costa fundamentally different from the entities handled by the standard 891e5671dfaSGlauber Costa Memory Controller, which are page-based, and can be swapped. Users of 892e5671dfaSGlauber Costa the kmem extension can use it to guarantee that no group of processes 893e5671dfaSGlauber Costa will ever exhaust kernel resources alone. 894c077719bSKAMEZAWA Hiroyuki 8952bc64a20SAneesh Kumar K.Vconfig CGROUP_HUGETLB 8962bc64a20SAneesh Kumar K.V bool "HugeTLB Resource Controller for Control Groups" 89719c92399SKees Cook depends on RESOURCE_COUNTERS && HUGETLB_PAGE 8982bc64a20SAneesh Kumar K.V default n 8992bc64a20SAneesh Kumar K.V help 9002bc64a20SAneesh Kumar K.V Provides a cgroup Resource Controller for HugeTLB pages. 9012bc64a20SAneesh Kumar K.V When you enable this, you can put a per cgroup limit on HugeTLB usage. 9022bc64a20SAneesh Kumar K.V The limit is enforced during page fault. Since HugeTLB doesn't 9032bc64a20SAneesh Kumar K.V support page reclaim, enforcing the limit at page fault time implies 9042bc64a20SAneesh Kumar K.V that, the application will get SIGBUS signal if it tries to access 9052bc64a20SAneesh Kumar K.V HugeTLB pages beyond its limit. This requires the application to know 9062bc64a20SAneesh Kumar K.V beforehand how much HugeTLB pages it would require for its use. The 9072bc64a20SAneesh Kumar K.V control group is tracked in the third page lru pointer. This means 9082bc64a20SAneesh Kumar K.V that we cannot use the controller with huge page less than 3 pages. 9092bc64a20SAneesh Kumar K.V 910e5d1367fSStephane Eranianconfig CGROUP_PERF 911e5d1367fSStephane Eranian bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" 912e5d1367fSStephane Eranian depends on PERF_EVENTS && CGROUPS 913e5d1367fSStephane Eranian help 914e5d1367fSStephane Eranian This option extends the per-cpu mode to restrict monitoring to 9152d0f2520SLi Zefan threads which belong to the cgroup specified and run on the 916e5d1367fSStephane Eranian designated cpu. 917e5d1367fSStephane Eranian 918e5d1367fSStephane Eranian Say N if unsure. 919e5d1367fSStephane Eranian 9207c941438SDhaval Gianimenuconfig CGROUP_SCHED 9217c941438SDhaval Giani bool "Group CPU scheduler" 9227c941438SDhaval Giani default n 9237c941438SDhaval Giani help 9247c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 9257c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 9267c941438SDhaval Giani tasks. 9277c941438SDhaval Giani 9287c941438SDhaval Gianiif CGROUP_SCHED 9297c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 9307c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 9317c941438SDhaval Giani depends on CGROUP_SCHED 9327c941438SDhaval Giani default CGROUP_SCHED 9337c941438SDhaval Giani 934ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 935ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 936ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 937ab84d31eSPaul Turner default n 938ab84d31eSPaul Turner help 939ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 940ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 941ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 942ab84d31eSPaul Turner restriction. 943ab84d31eSPaul Turner See tip/Documentation/scheduler/sched-bwc.txt for more information. 944ab84d31eSPaul Turner 9457c941438SDhaval Gianiconfig RT_GROUP_SCHED 9467c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 9477c941438SDhaval Giani depends on CGROUP_SCHED 9487c941438SDhaval Giani default n 9497c941438SDhaval Giani help 9507c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 95132bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 9527c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 9537c941438SDhaval Giani realtime bandwidth for them. 9547c941438SDhaval Giani See Documentation/scheduler/sched-rt-group.txt for more information. 9557c941438SDhaval Giani 9567c941438SDhaval Gianiendif #CGROUP_SCHED 9577c941438SDhaval Giani 958afc24d49SVivek Goyalconfig BLK_CGROUP 95932e380aeSTejun Heo bool "Block IO controller" 96079ae9c29SDaniel Lezcano depends on BLOCK 961afc24d49SVivek Goyal default n 962afc24d49SVivek Goyal ---help--- 963afc24d49SVivek Goyal Generic block IO controller cgroup interface. This is the common 964afc24d49SVivek Goyal cgroup interface which should be used by various IO controlling 965afc24d49SVivek Goyal policies. 966afc24d49SVivek Goyal 967afc24d49SVivek Goyal Currently, CFQ IO scheduler uses it to recognize task groups and 968afc24d49SVivek Goyal control disk bandwidth allocation (proportional time slice allocation) 969e43473b7SVivek Goyal to such task groups. It is also used by bio throttling logic in 970e43473b7SVivek Goyal block layer to implement upper limit in IO rates on a device. 971afc24d49SVivek Goyal 972afc24d49SVivek Goyal This option only enables generic Block IO controller infrastructure. 973e43473b7SVivek Goyal One needs to also enable actual IO controlling logic/policy. For 97479e2e759SMichael Witten enabling proportional weight division of disk bandwidth in CFQ, set 97579e2e759SMichael Witten CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 976c5e0591aSMichael Witten CONFIG_BLK_DEV_THROTTLING=y. 977afc24d49SVivek Goyal 978afc24d49SVivek Goyal See Documentation/cgroups/blkio-controller.txt for more information. 979afc24d49SVivek Goyal 980afc24d49SVivek Goyalconfig DEBUG_BLK_CGROUP 981afc24d49SVivek Goyal bool "Enable Block IO controller debugging" 982afc24d49SVivek Goyal depends on BLK_CGROUP 983afc24d49SVivek Goyal default n 984afc24d49SVivek Goyal ---help--- 985afc24d49SVivek Goyal Enable some debugging help. Currently it exports additional stat 986afc24d49SVivek Goyal files in a cgroup which can be useful for debugging. 987afc24d49SVivek Goyal 98823964d2dSLi Zefanendif # CGROUPS 989c077719bSKAMEZAWA Hiroyuki 990067bce1aSCyrill Gorcunovconfig CHECKPOINT_RESTORE 991067bce1aSCyrill Gorcunov bool "Checkpoint/restore support" if EXPERT 992067bce1aSCyrill Gorcunov default n 993067bce1aSCyrill Gorcunov help 994067bce1aSCyrill Gorcunov Enables additional kernel features in a sake of checkpoint/restore. 995067bce1aSCyrill Gorcunov In particular it adds auxiliary prctl codes to setup process text, 996067bce1aSCyrill Gorcunov data and heap segment sizes, and a few additional /proc filesystem 997067bce1aSCyrill Gorcunov entries. 998067bce1aSCyrill Gorcunov 999067bce1aSCyrill Gorcunov If unsure, say N here. 1000067bce1aSCyrill Gorcunov 10018dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 10026a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 10036a108a14SDavid Rientjes default !EXPERT 1004c5289a69SPavel Emelyanov help 1005c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 1006c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 1007c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 1008c5289a69SPavel Emelyanov different namespaces. 1009c5289a69SPavel Emelyanov 10108dd2a82cSDaniel Lezcanoif NAMESPACES 10118dd2a82cSDaniel Lezcano 101258bfdd6dSPavel Emelyanovconfig UTS_NS 101358bfdd6dSPavel Emelyanov bool "UTS namespace" 101417a6d441SDaniel Lezcano default y 101558bfdd6dSPavel Emelyanov help 101658bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 101758bfdd6dSPavel Emelyanov uname() system call 101858bfdd6dSPavel Emelyanov 1019ae5e1b22SPavel Emelyanovconfig IPC_NS 1020ae5e1b22SPavel Emelyanov bool "IPC namespace" 10218dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 102217a6d441SDaniel Lezcano default y 1023ae5e1b22SPavel Emelyanov help 1024ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 1025614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 1026ae5e1b22SPavel Emelyanov 1027aee16ce7SPavel Emelyanovconfig USER_NS 102819c92399SKees Cook bool "User namespace" 1029e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 10305673a94cSEric W. Biederman select UIDGID_STRICT_TYPE_CHECKS 1031e1c972b6SEric W. Biederman 10325673a94cSEric W. Biederman default n 1033aee16ce7SPavel Emelyanov help 1034aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 1035aee16ce7SPavel Emelyanov to provide different user info for different servers. 1036e11f0ae3SEric W. Biederman 1037e11f0ae3SEric W. Biederman When user namespaces are enabled in the kernel it is 1038e11f0ae3SEric W. Biederman recommended that the MEMCG and MEMCG_KMEM options also be 1039e11f0ae3SEric W. Biederman enabled and that user-space use the memory control groups to 1040e11f0ae3SEric W. Biederman limit the amount of memory a memory unprivileged users can 1041e11f0ae3SEric W. Biederman use. 1042e11f0ae3SEric W. Biederman 1043aee16ce7SPavel Emelyanov If unsure, say N. 1044aee16ce7SPavel Emelyanov 104574bd59bbSPavel Emelyanovconfig PID_NS 10469bd38c2cSDaniel Lezcano bool "PID Namespaces" 104717a6d441SDaniel Lezcano default y 104874bd59bbSPavel Emelyanov help 104912d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 1050692105b8SMatt LaPlante processes with the same pid as long as they are in different 105174bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 105274bd59bbSPavel Emelyanov 1053d6eb633fSMatt Helsleyconfig NET_NS 1054d6eb633fSMatt Helsley bool "Network namespace" 10558dd2a82cSDaniel Lezcano depends on NET 105617a6d441SDaniel Lezcano default y 1057d6eb633fSMatt Helsley help 1058d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 1059d6eb633fSMatt Helsley of the network stack. 1060d6eb633fSMatt Helsley 10618dd2a82cSDaniel Lezcanoendif # NAMESPACES 10628dd2a82cSDaniel Lezcano 1063e1c972b6SEric W. Biedermanconfig UIDGID_CONVERTED 1064e1c972b6SEric W. Biederman # True if all of the selected software conmponents are known 1065e1c972b6SEric W. Biederman # to have uid_t and gid_t converted to kuid_t and kgid_t 1066e1c972b6SEric W. Biederman # where appropriate and are otherwise safe to use with 1067e1c972b6SEric W. Biederman # the user namespace. 1068e1c972b6SEric W. Biederman bool 1069e1c972b6SEric W. Biederman default y 1070e1c972b6SEric W. Biederman 1071e1c972b6SEric W. Biederman # Filesystems 1072e1c972b6SEric W. Biederman depends on XFS_FS = n 1073e1c972b6SEric W. Biederman 10745673a94cSEric W. Biedermanconfig UIDGID_STRICT_TYPE_CHECKS 10755673a94cSEric W. Biederman bool "Require conversions between uid/gids and their internal representation" 1076e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 10775673a94cSEric W. Biederman default n 10785673a94cSEric W. Biederman help 10795673a94cSEric W. Biederman While the nececessary conversions are being added to all subsystems this option allows 10805673a94cSEric W. Biederman the code to continue to build for unconverted subsystems. 10815673a94cSEric W. Biederman 10825673a94cSEric W. Biederman Say Y here if you want the strict type checking enabled 10835673a94cSEric W. Biederman 10845091faa4SMike Galbraithconfig SCHED_AUTOGROUP 10855091faa4SMike Galbraith bool "Automatic process group scheduling" 10865091faa4SMike Galbraith select EVENTFD 10875091faa4SMike Galbraith select CGROUPS 10885091faa4SMike Galbraith select CGROUP_SCHED 10895091faa4SMike Galbraith select FAIR_GROUP_SCHED 10905091faa4SMike Galbraith help 10915091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 10925091faa4SMike Galbraith automatically creating and populating task groups. This separation 10935091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 10945091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 10955091faa4SMike Galbraith upon task session. 10965091faa4SMike Galbraith 10977af37becSDaniel Lezcanoconfig MM_OWNER 10987af37becSDaniel Lezcano bool 10997af37becSDaniel Lezcano 11007af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED 11015d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features to support old userspace tools" 11027af37becSDaniel Lezcano depends on SYSFS 11037af37becSDaniel Lezcano default n 11047af37becSDaniel Lezcano help 11057af37becSDaniel Lezcano This option adds code that switches the layout of the "block" class 11067af37becSDaniel Lezcano devices, to not show up in /sys/class/block/, but only in 11077af37becSDaniel Lezcano /sys/block/. 11087af37becSDaniel Lezcano 11097af37becSDaniel Lezcano This switch is only active when the sysfs.deprecated=1 boot option is 11107af37becSDaniel Lezcano passed or the SYSFS_DEPRECATED_V2 option is set. 11117af37becSDaniel Lezcano 11127af37becSDaniel Lezcano This option allows new kernels to run on old distributions and tools, 11137af37becSDaniel Lezcano which might get confused by /sys/class/block/. Since 2007/2008 all 11147af37becSDaniel Lezcano major distributions and tools handle this just fine. 11157af37becSDaniel Lezcano 11167af37becSDaniel Lezcano Recent distributions and userspace tools after 2009/2010 depend on 11177af37becSDaniel Lezcano the existence of /sys/class/block/, and will not work with this 11187af37becSDaniel Lezcano option enabled. 11197af37becSDaniel Lezcano 11207af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 11217af37becSDaniel Lezcano need to say Y here. 11227af37becSDaniel Lezcano 11237af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED_V2 11245d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features by default" 11257af37becSDaniel Lezcano default n 11267af37becSDaniel Lezcano depends on SYSFS 11277af37becSDaniel Lezcano depends on SYSFS_DEPRECATED 11287af37becSDaniel Lezcano help 11297af37becSDaniel Lezcano Enable deprecated sysfs by default. 11307af37becSDaniel Lezcano 11317af37becSDaniel Lezcano See the CONFIG_SYSFS_DEPRECATED option for more details about this 11327af37becSDaniel Lezcano option. 11337af37becSDaniel Lezcano 11347af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 11357af37becSDaniel Lezcano need to say Y here. Even then, odds are you would not need it 11367af37becSDaniel Lezcano enabled, you can always pass the boot option if absolutely necessary. 11377af37becSDaniel Lezcano 11387af37becSDaniel Lezcanoconfig RELAY 11397af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 11407af37becSDaniel Lezcano help 11417af37becSDaniel Lezcano This option enables support for relay interface support in 11427af37becSDaniel Lezcano certain file systems (such as debugfs). 11437af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 11447af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 11457af37becSDaniel Lezcano user space. 11467af37becSDaniel Lezcano 11477af37becSDaniel Lezcano If unsure, say N. 11487af37becSDaniel Lezcano 1149f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1150f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1151f991633dSDimitri Gorokhovik depends on BROKEN || !FRV 1152f991633dSDimitri Gorokhovik help 1153f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1154f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1155f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1156f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 1157f991633dSDimitri Gorokhovik etc. See <file:Documentation/initrd.txt> for details. 1158f991633dSDimitri Gorokhovik 1159f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1160f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1161f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1162f991633dSDimitri Gorokhovik 1163f991633dSDimitri Gorokhovik If unsure say Y. 1164f991633dSDimitri Gorokhovik 1165c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1166c33df4eaSJean-Paul Saman 1167dbec4866SSam Ravnborgsource "usr/Kconfig" 1168dbec4866SSam Ravnborg 1169c33df4eaSJean-Paul Samanendif 1170c33df4eaSJean-Paul Saman 1171c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 117296fffeb4SIngo Molnar bool "Optimize for size" 1173c45b4f1fSLinus Torvalds help 1174c45b4f1fSLinus Torvalds Enabling this option will pass "-Os" instead of "-O2" to gcc 1175c45b4f1fSLinus Torvalds resulting in a smaller kernel. 1176c45b4f1fSLinus Torvalds 11773a55fb0dSKirill Smelkov If unsure, say N. 1178c45b4f1fSLinus Torvalds 11790847062aSRandy Dunlapconfig SYSCTL 11800847062aSRandy Dunlap bool 11810847062aSRandy Dunlap 1182b943c460SRandy Dunlapconfig ANON_INODES 1183b943c460SRandy Dunlap bool 1184b943c460SRandy Dunlap 11856a108a14SDavid Rientjesmenuconfig EXPERT 11866a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1187f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1188f505c553SJosh Triplett select DEBUG_KERNEL 11891da177e4SLinus Torvalds help 11901da177e4SLinus Torvalds This option allows certain base kernel options and settings 11911da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 11921da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 11931da177e4SLinus Torvalds Only use this if you really know what you are doing. 11941da177e4SLinus Torvalds 1195af1839ebSCatalin Marinasconfig HAVE_UID16 1196af1839ebSCatalin Marinas bool 1197af1839ebSCatalin Marinas 1198ae81f9e3SChuck Ebbertconfig UID16 11996a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 1200af1839ebSCatalin Marinas depends on HAVE_UID16 1201ae81f9e3SChuck Ebbert default y 1202ae81f9e3SChuck Ebbert help 1203ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1204ae81f9e3SChuck Ebbert 1205b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL 12066a108a14SDavid Rientjes bool "Sysctl syscall support" if EXPERT 120726a7034bSEric W. Biederman depends on PROC_SYSCTL 1208c736de60SWANG Cong default n 1209b89a8171SEric W. Biederman select SYSCTL 1210b89a8171SEric W. Biederman ---help--- 121113bb7e37SEric W. Biederman sys_sysctl uses binary paths that have been found challenging 121213bb7e37SEric W. Biederman to properly maintain and use. The interface in /proc/sys 121313bb7e37SEric W. Biederman using paths with ascii names is now the primary path to this 121413bb7e37SEric W. Biederman information. 1215b89a8171SEric W. Biederman 121613bb7e37SEric W. Biederman Almost nothing using the binary sysctl interface so if you are 121713bb7e37SEric W. Biederman trying to save some space it is probably safe to disable this, 121813bb7e37SEric W. Biederman making your kernel marginally smaller. 1219b89a8171SEric W. Biederman 1220c736de60SWANG Cong If unsure say N here. 1221ae81f9e3SChuck Ebbert 12227ac57a89SCatalin Marinasconfig SYSCTL_EXCEPTION_TRACE 12237ac57a89SCatalin Marinas bool 12247ac57a89SCatalin Marinas help 12257ac57a89SCatalin Marinas Enable support for /proc/sys/debug/exception-trace. 12267ac57a89SCatalin Marinas 1227b6fca725SVineet Guptaconfig SYSCTL_ARCH_UNALIGN_NO_WARN 1228b6fca725SVineet Gupta bool 1229b6fca725SVineet Gupta help 1230b6fca725SVineet Gupta Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1231b6fca725SVineet Gupta Allows arch to define/use @no_unaligned_warning to possibly warn 1232b6fca725SVineet Gupta about unaligned access emulation going on under the hood. 1233b6fca725SVineet Gupta 1234bf14e3b9SVineet Guptaconfig SYSCTL_ARCH_UNALIGN_ALLOW 1235bf14e3b9SVineet Gupta bool 1236bf14e3b9SVineet Gupta help 1237bf14e3b9SVineet Gupta Enable support for /proc/sys/kernel/unaligned-trap 1238bf14e3b9SVineet Gupta Allows arches to define/use @unaligned_enabled to runtime toggle 1239bf14e3b9SVineet Gupta the unaligned access emulation. 1240bf14e3b9SVineet Gupta see arch/parisc/kernel/unaligned.c for reference 1241bf14e3b9SVineet Gupta 12421da177e4SLinus Torvaldsconfig KALLSYMS 12436a108a14SDavid Rientjes bool "Load all symbols for debugging/ksymoops" if EXPERT 12441da177e4SLinus Torvalds default y 12451da177e4SLinus Torvalds help 12461da177e4SLinus Torvalds Say Y here to let the kernel print out symbolic crash information and 12471da177e4SLinus Torvalds symbolic stack backtraces. This increases the size of the kernel 12481da177e4SLinus Torvalds somewhat, as all symbols have to be loaded into the kernel image. 12491da177e4SLinus Torvalds 12501da177e4SLinus Torvaldsconfig KALLSYMS_ALL 12511da177e4SLinus Torvalds bool "Include all symbols in kallsyms" 12521da177e4SLinus Torvalds depends on DEBUG_KERNEL && KALLSYMS 12531da177e4SLinus Torvalds help 125471a83ec7SArtem Bityutskiy Normally kallsyms only contains the symbols of functions for nicer 125571a83ec7SArtem Bityutskiy OOPS messages and backtraces (i.e., symbols from the text and inittext 125671a83ec7SArtem Bityutskiy sections). This is sufficient for most cases. And only in very rare 125771a83ec7SArtem Bityutskiy cases (e.g., when a debugger is used) all symbols are required (e.g., 125871a83ec7SArtem Bityutskiy names of variables from the data sections, etc). 12591da177e4SLinus Torvalds 126071a83ec7SArtem Bityutskiy This option makes sure that all symbols are loaded into the kernel 126171a83ec7SArtem Bityutskiy image (i.e., symbols from all sections) in cost of increased kernel 126271a83ec7SArtem Bityutskiy size (depending on the kernel configuration, it may be 300KiB or 126371a83ec7SArtem Bityutskiy something like this). 12641da177e4SLinus Torvalds 126571a83ec7SArtem Bityutskiy Say N unless you really need all symbols. 1266d59745ceSMatt Mackall 1267712f47ceSGreg Kroah-Hartmanconfig HOTPLUG 126845f035abSGreg Kroah-Hartman def_bool y 1269712f47ceSGreg Kroah-Hartman 1270d59745ceSMatt Mackallconfig PRINTK 1271d59745ceSMatt Mackall default y 12726a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 127374876a98SFrederic Weisbecker select IRQ_WORK 1274d59745ceSMatt Mackall help 1275d59745ceSMatt Mackall This option enables normal printk support. Removing it 1276d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1277d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1278d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1279d59745ceSMatt Mackall strongly discouraged. 1280d59745ceSMatt Mackall 1281c8538a7aSMatt Mackallconfig BUG 12826a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1283c8538a7aSMatt Mackall default y 1284c8538a7aSMatt Mackall help 1285c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1286c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1287c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1288c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1289c8538a7aSMatt Mackall Just say Y. 1290c8538a7aSMatt Mackall 1291708e9a79SMatt Mackallconfig ELF_CORE 1292046d662fSAlex Kelly depends on COREDUMP 1293708e9a79SMatt Mackall default y 12946a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1295708e9a79SMatt Mackall help 1296708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1297708e9a79SMatt Mackall 12988761f1abSRalf Baechle 1299e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 13006a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 13018761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 130215f304b6SRalf Baechle select I8253_LOCK 1303e5e1d3cbSStas Sergeev default y 1304e5e1d3cbSStas Sergeev help 1305e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1306e5e1d3cbSStas Sergeev support, saving some memory. 1307e5e1d3cbSStas Sergeev 13088761f1abSRalf Baechleconfig HAVE_PCSPKR_PLATFORM 13098761f1abSRalf Baechle bool 13108761f1abSRalf Baechle 13111da177e4SLinus Torvaldsconfig BASE_FULL 13121da177e4SLinus Torvalds default y 13136a108a14SDavid Rientjes bool "Enable full-sized data structures for core" if EXPERT 13141da177e4SLinus Torvalds help 13151da177e4SLinus Torvalds Disabling this option reduces the size of miscellaneous core 13161da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 13171da177e4SLinus Torvalds but may reduce performance. 13181da177e4SLinus Torvalds 13191da177e4SLinus Torvaldsconfig FUTEX 13206a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 13211da177e4SLinus Torvalds default y 132223f78d4aSIngo Molnar select RT_MUTEXES 13231da177e4SLinus Torvalds help 13241da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 13251da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 13261da177e4SLinus Torvalds run glibc-based applications correctly. 13271da177e4SLinus Torvalds 13281da177e4SLinus Torvaldsconfig EPOLL 13296a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 13301da177e4SLinus Torvalds default y 1331448e3ceeSAdrian Bunk select ANON_INODES 13321da177e4SLinus Torvalds help 13331da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 13341da177e4SLinus Torvalds support for epoll family of system calls. 13351da177e4SLinus Torvalds 1336fba2afaaSDavide Libenziconfig SIGNALFD 13376a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1338448e3ceeSAdrian Bunk select ANON_INODES 1339fba2afaaSDavide Libenzi default y 1340fba2afaaSDavide Libenzi help 1341fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1342fba2afaaSDavide Libenzi on a file descriptor. 1343fba2afaaSDavide Libenzi 1344fba2afaaSDavide Libenzi If unsure, say Y. 1345fba2afaaSDavide Libenzi 1346b215e283SDavide Libenziconfig TIMERFD 13476a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1348448e3ceeSAdrian Bunk select ANON_INODES 1349b215e283SDavide Libenzi default y 1350b215e283SDavide Libenzi help 1351b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1352b215e283SDavide Libenzi events on a file descriptor. 1353b215e283SDavide Libenzi 1354b215e283SDavide Libenzi If unsure, say Y. 1355b215e283SDavide Libenzi 1356e1ad7468SDavide Libenziconfig EVENTFD 13576a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1358448e3ceeSAdrian Bunk select ANON_INODES 1359e1ad7468SDavide Libenzi default y 1360e1ad7468SDavide Libenzi help 1361e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1362e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1363e1ad7468SDavide Libenzi 1364e1ad7468SDavide Libenzi If unsure, say Y. 1365e1ad7468SDavide Libenzi 13661da177e4SLinus Torvaldsconfig SHMEM 13676a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 13681da177e4SLinus Torvalds default y 13691da177e4SLinus Torvalds depends on MMU 13701da177e4SLinus Torvalds help 13711da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 13721da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 13731da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 13741da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 13751da177e4SLinus Torvalds which may be appropriate on small systems without swap. 13761da177e4SLinus Torvalds 1377ebf3f09cSThomas Petazzoniconfig AIO 13786a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1379ebf3f09cSThomas Petazzoni default y 1380ebf3f09cSThomas Petazzoni help 1381ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1382ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1383ebf3f09cSThomas Petazzoni this option saves about 7k. 1384ebf3f09cSThomas Petazzoni 13856befe5f6SRandy Dunlapconfig EMBEDDED 13866befe5f6SRandy Dunlap bool "Embedded system" 13876befe5f6SRandy Dunlap select EXPERT 13886befe5f6SRandy Dunlap help 13896befe5f6SRandy Dunlap This option should be enabled if compiling the kernel for 13906befe5f6SRandy Dunlap an embedded system so certain expert options are available 13916befe5f6SRandy Dunlap for configuration. 13926befe5f6SRandy Dunlap 1393cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 13940793a61dSThomas Gleixner bool 1395018df72dSMike Frysinger help 1396018df72dSMike Frysinger See tools/perf/design.txt for details. 13970793a61dSThomas Gleixner 1398906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 1399906010b2SPeter Zijlstra bool 1400906010b2SPeter Zijlstra help 1401906010b2SPeter Zijlstra See tools/perf/design.txt for details 1402906010b2SPeter Zijlstra 140357c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 14040793a61dSThomas Gleixner 1405cdd6c482SIngo Molnarconfig PERF_EVENTS 140657c0c15bSIngo Molnar bool "Kernel performance events and counters" 1407392d65a9SRobert Richter default y if PROFILING 1408cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 14094c59e467SIngo Molnar select ANON_INODES 1410e360adbeSPeter Zijlstra select IRQ_WORK 14110793a61dSThomas Gleixner help 141257c0c15bSIngo Molnar Enable kernel support for various performance events provided 141357c0c15bSIngo Molnar by software and hardware. 14140793a61dSThomas Gleixner 1415dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 141657c0c15bSIngo Molnar use of generic tracepoints. 141757c0c15bSIngo Molnar 141857c0c15bSIngo Molnar Most modern CPUs support performance events via performance 141957c0c15bSIngo Molnar counter registers. These registers count the number of certain 14200793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 14210793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 14220793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 14230793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 14240793a61dSThomas Gleixner used to profile the code that runs on that CPU. 14250793a61dSThomas Gleixner 142657c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 1427dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 142857c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 14290793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 14300793a61dSThomas Gleixner capabilities on top of those. 14310793a61dSThomas Gleixner 14320793a61dSThomas Gleixner Say Y if unsure. 14330793a61dSThomas Gleixner 1434906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 1435906010b2SPeter Zijlstra default n 1436906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 1437906010b2SPeter Zijlstra depends on PERF_EVENTS && DEBUG_KERNEL 1438906010b2SPeter Zijlstra select PERF_USE_VMALLOC 1439906010b2SPeter Zijlstra help 1440906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 1441906010b2SPeter Zijlstra 1442906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 1443906010b2SPeter Zijlstra that don't require it. 1444906010b2SPeter Zijlstra 1445906010b2SPeter Zijlstra Say N if unsure. 1446906010b2SPeter Zijlstra 14470793a61dSThomas Gleixnerendmenu 14480793a61dSThomas Gleixner 1449f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS 1450f8891e5eSChristoph Lameter default y 14516a108a14SDavid Rientjes bool "Enable VM event counters for /proc/vmstat" if EXPERT 1452f8891e5eSChristoph Lameter help 14532aea4fb6SPaul Jackson VM event counters are needed for event counts to be shown. 14542aea4fb6SPaul Jackson This option allows the disabling of the VM event counters 14556a108a14SDavid Rientjes on EXPERT systems. /proc/vmstat will only show page counts 14562aea4fb6SPaul Jackson if VM event counters are disabled. 1457f8891e5eSChristoph Lameter 14583d137310SThomas Petazzoniconfig PCI_QUIRKS 14593d137310SThomas Petazzoni default y 14606a108a14SDavid Rientjes bool "Enable PCI quirk workarounds" if EXPERT 146161cfc7e4SGeert Uytterhoeven depends on PCI 14623d137310SThomas Petazzoni help 14633d137310SThomas Petazzoni This enables workarounds for various PCI chipset 14643d137310SThomas Petazzoni bugs/quirks. Disable this only if your target machine is 14653d137310SThomas Petazzoni unaffected by PCI quirks. 14663d137310SThomas Petazzoni 146741ecc55bSChristoph Lameterconfig SLUB_DEBUG 146841ecc55bSChristoph Lameter default y 14696a108a14SDavid Rientjes bool "Enable SLUB debugging support" if EXPERT 1470f6acb635SChristoph Lameter depends on SLUB && SYSFS 147141ecc55bSChristoph Lameter help 147241ecc55bSChristoph Lameter SLUB has extensive debug support features. Disabling these can 147341ecc55bSChristoph Lameter result in significant savings in code size. This also disables 147441ecc55bSChristoph Lameter SLUB sysfs support. /sys/slab will not exist and there will be 147541ecc55bSChristoph Lameter no support for cache validation etc. 147641ecc55bSChristoph Lameter 1477b943c460SRandy Dunlapconfig COMPAT_BRK 1478b943c460SRandy Dunlap bool "Disable heap randomization" 1479b943c460SRandy Dunlap default y 1480b943c460SRandy Dunlap help 1481b943c460SRandy Dunlap Randomizing heap placement makes heap exploits harder, but it 1482b943c460SRandy Dunlap also breaks ancient binaries (including anything libc5 based). 1483b943c460SRandy Dunlap This option changes the bootup default to heap randomization 1484692105b8SMatt LaPlante disabled, and can be overridden at runtime by setting 1485b943c460SRandy Dunlap /proc/sys/kernel/randomize_va_space to 2. 1486b943c460SRandy Dunlap 1487b943c460SRandy Dunlap On non-ancient distros (post-2000 ones) N is usually a safe choice. 1488b943c460SRandy Dunlap 148981819f0fSChristoph Lameterchoice 149081819f0fSChristoph Lameter prompt "Choose SLAB allocator" 1491a0acd820SChristoph Lameter default SLUB 149281819f0fSChristoph Lameter help 149381819f0fSChristoph Lameter This option allows to select a slab allocator. 149481819f0fSChristoph Lameter 149581819f0fSChristoph Lameterconfig SLAB 149681819f0fSChristoph Lameter bool "SLAB" 149781819f0fSChristoph Lameter help 149881819f0fSChristoph Lameter The regular slab allocator that is established and known to work 149934013886SChristoph Lameter well in all environments. It organizes cache hot objects in 150002f56210SSimon Arlott per cpu and per node queues. 150181819f0fSChristoph Lameter 150281819f0fSChristoph Lameterconfig SLUB 150381819f0fSChristoph Lameter bool "SLUB (Unqueued Allocator)" 150481819f0fSChristoph Lameter help 150581819f0fSChristoph Lameter SLUB is a slab allocator that minimizes cache line usage 150681819f0fSChristoph Lameter instead of managing queues of cached objects (SLAB approach). 150781819f0fSChristoph Lameter Per cpu caching is realized using slabs of objects instead 150881819f0fSChristoph Lameter of queues of objects. SLUB can use memory efficiently 150902f56210SSimon Arlott and has enhanced diagnostics. SLUB is the default choice for 151002f56210SSimon Arlott a slab allocator. 151181819f0fSChristoph Lameter 151281819f0fSChristoph Lameterconfig SLOB 15136a108a14SDavid Rientjes depends on EXPERT 151481819f0fSChristoph Lameter bool "SLOB (Simple Allocator)" 151581819f0fSChristoph Lameter help 151637291458SMatt Mackall SLOB replaces the stock allocator with a drastically simpler 151737291458SMatt Mackall allocator. SLOB is generally more space efficient but 151837291458SMatt Mackall does not perform as well on large systems. 151981819f0fSChristoph Lameter 152081819f0fSChristoph Lameterendchoice 152181819f0fSChristoph Lameter 1522ea637639SJie Zhangconfig MMAP_ALLOW_UNINITIALIZED 1523ea637639SJie Zhang bool "Allow mmapped anonymous memory to be uninitialized" 15246a108a14SDavid Rientjes depends on EXPERT && !MMU 1525ea637639SJie Zhang default n 1526ea637639SJie Zhang help 1527ea637639SJie Zhang Normally, and according to the Linux spec, anonymous memory obtained 1528ea637639SJie Zhang from mmap() has it's contents cleared before it is passed to 1529ea637639SJie Zhang userspace. Enabling this config option allows you to request that 1530ea637639SJie Zhang mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus 1531ea637639SJie Zhang providing a huge performance boost. If this option is not enabled, 1532ea637639SJie Zhang then the flag will be ignored. 1533ea637639SJie Zhang 1534ea637639SJie Zhang This is taken advantage of by uClibc's malloc(), and also by 1535ea637639SJie Zhang ELF-FDPIC binfmt's brk and stack allocator. 1536ea637639SJie Zhang 1537ea637639SJie Zhang Because of the obvious security issues, this option should only be 1538ea637639SJie Zhang enabled on embedded devices where you control what is run in 1539ea637639SJie Zhang userspace. Since that isn't generally a problem on no-MMU systems, 1540ea637639SJie Zhang it is normally safe to say Y here. 1541ea637639SJie Zhang 1542ea637639SJie Zhang See Documentation/nommu-mmap.txt for more information. 1543ea637639SJie Zhang 1544125e5645SMathieu Desnoyersconfig PROFILING 1545b309a294SRobert Richter bool "Profiling support" 1546125e5645SMathieu Desnoyers help 1547125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 1548125e5645SMathieu Desnoyers by profilers such as OProfile. 1549125e5645SMathieu Desnoyers 15505f87f112SIngo Molnar# 15515f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 15525f87f112SIngo Molnar# dynamically changed for a probe function. 15535f87f112SIngo Molnar# 155497e1c18eSMathieu Desnoyersconfig TRACEPOINTS 15555f87f112SIngo Molnar bool 155697e1c18eSMathieu Desnoyers 1557fb32e03fSMathieu Desnoyerssource "arch/Kconfig" 1558fb32e03fSMathieu Desnoyers 15591da177e4SLinus Torvaldsendmenu # General setup 15601da177e4SLinus Torvalds 1561ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT 1562ee7e5516SDmitry Baryshkov bool 1563ee7e5516SDmitry Baryshkov default n 1564ee7e5516SDmitry Baryshkov 1565158a9624SLinus Torvaldsconfig SLABINFO 1566158a9624SLinus Torvalds bool 1567158a9624SLinus Torvalds depends on PROC_FS 15680f389ec6SChristoph Lameter depends on SLAB || SLUB_DEBUG 1569158a9624SLinus Torvalds default y 1570158a9624SLinus Torvalds 1571ae81f9e3SChuck Ebbertconfig RT_MUTEXES 1572ae81f9e3SChuck Ebbert boolean 1573ae81f9e3SChuck Ebbert 15741da177e4SLinus Torvaldsconfig BASE_SMALL 15751da177e4SLinus Torvalds int 15761da177e4SLinus Torvalds default 0 if BASE_FULL 15771da177e4SLinus Torvalds default 1 if !BASE_FULL 15781da177e4SLinus Torvalds 157966da5733SJan Engelhardtmenuconfig MODULES 15801da177e4SLinus Torvalds bool "Enable loadable module support" 15811da177e4SLinus Torvalds help 15821da177e4SLinus Torvalds Kernel modules are small pieces of compiled code which can 15831da177e4SLinus Torvalds be inserted in the running kernel, rather than being 15841da177e4SLinus Torvalds permanently built into the kernel. You use the "modprobe" 15851da177e4SLinus Torvalds tool to add (and sometimes remove) them. If you say Y here, 15861da177e4SLinus Torvalds many parts of the kernel can be built as modules (by 15871da177e4SLinus Torvalds answering M instead of Y where indicated): this is most 15881da177e4SLinus Torvalds useful for infrequently used options which are not required 15891da177e4SLinus Torvalds for booting. For more information, see the man pages for 15901da177e4SLinus Torvalds modprobe, lsmod, modinfo, insmod and rmmod. 15911da177e4SLinus Torvalds 15921da177e4SLinus Torvalds If you say Y here, you will need to run "make 15931da177e4SLinus Torvalds modules_install" to put the modules under /lib/modules/ 15941da177e4SLinus Torvalds where modprobe can find them (you may need to be root to do 15951da177e4SLinus Torvalds this). 15961da177e4SLinus Torvalds 15971da177e4SLinus Torvalds If unsure, say Y. 15981da177e4SLinus Torvalds 15990b0de144SRobert P. J. Dayif MODULES 16000b0de144SRobert P. J. Day 1601826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD 1602826e4506SLinus Torvalds bool "Forced module loading" 1603826e4506SLinus Torvalds default n 1604826e4506SLinus Torvalds help 160591e37a79SRusty Russell Allow loading of modules without version information (ie. modprobe 160691e37a79SRusty Russell --force). Forced module loading sets the 'F' (forced) taint flag and 160791e37a79SRusty Russell is usually a really bad idea. 1608826e4506SLinus Torvalds 16091da177e4SLinus Torvaldsconfig MODULE_UNLOAD 16101da177e4SLinus Torvalds bool "Module unloading" 16111da177e4SLinus Torvalds help 16121da177e4SLinus Torvalds Without this option you will not be able to unload any 16131da177e4SLinus Torvalds modules (note that some modules may not be unloadable 1614f7f5b675SDenys Vlasenko anyway), which makes your kernel smaller, faster 1615f7f5b675SDenys Vlasenko and simpler. If unsure, say Y. 16161da177e4SLinus Torvalds 16171da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD 16181da177e4SLinus Torvalds bool "Forced module unloading" 161919c92399SKees Cook depends on MODULE_UNLOAD 16201da177e4SLinus Torvalds help 16211da177e4SLinus Torvalds This option allows you to force a module to unload, even if the 16221da177e4SLinus Torvalds kernel believes it is unsafe: the kernel will remove the module 16231da177e4SLinus Torvalds without waiting for anyone to stop using it (using the -f option to 16241da177e4SLinus Torvalds rmmod). This is mainly for kernel developers and desperate users. 16251da177e4SLinus Torvalds If unsure, say N. 16261da177e4SLinus Torvalds 16271da177e4SLinus Torvaldsconfig MODVERSIONS 16280d541643SSam Ravnborg bool "Module versioning support" 16291da177e4SLinus Torvalds help 16301da177e4SLinus Torvalds Usually, you have to use modules compiled with your kernel. 16311da177e4SLinus Torvalds Saying Y here makes it sometimes possible to use modules 16321da177e4SLinus Torvalds compiled for different kernels, by adding enough information 16331da177e4SLinus Torvalds to the modules to (hopefully) spot any changes which would 16341da177e4SLinus Torvalds make them incompatible with the kernel you are running. If 16351da177e4SLinus Torvalds unsure, say N. 16361da177e4SLinus Torvalds 16371da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL 16381da177e4SLinus Torvalds bool "Source checksum for all modules" 16391da177e4SLinus Torvalds help 16401da177e4SLinus Torvalds Modules which contain a MODULE_VERSION get an extra "srcversion" 16411da177e4SLinus Torvalds field inserted into their modinfo section, which contains a 16421da177e4SLinus Torvalds sum of the source files which made it. This helps maintainers 16431da177e4SLinus Torvalds see exactly which source was used to build a module (since 16441da177e4SLinus Torvalds others sometimes change the module source without updating 16451da177e4SLinus Torvalds the version). With this option, such a "srcversion" field 16461da177e4SLinus Torvalds will be created for all modules. If unsure, say N. 16471da177e4SLinus Torvalds 1648106a4ee2SRusty Russellconfig MODULE_SIG 1649106a4ee2SRusty Russell bool "Module signature verification" 1650106a4ee2SRusty Russell depends on MODULES 165148ba2462SDavid Howells select KEYS 165248ba2462SDavid Howells select CRYPTO 165348ba2462SDavid Howells select ASYMMETRIC_KEY_TYPE 165448ba2462SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 165548ba2462SDavid Howells select PUBLIC_KEY_ALGO_RSA 165648ba2462SDavid Howells select ASN1 165748ba2462SDavid Howells select OID_REGISTRY 165848ba2462SDavid Howells select X509_CERTIFICATE_PARSER 1659106a4ee2SRusty Russell help 1660106a4ee2SRusty Russell Check modules for valid signatures upon load: the signature 1661106a4ee2SRusty Russell is simply appended to the module. For more information see 1662106a4ee2SRusty Russell Documentation/module-signing.txt. 1663106a4ee2SRusty Russell 1664ea0b6dcfSDavid Howells !!!WARNING!!! If you enable this option, you MUST make sure that the 1665ea0b6dcfSDavid Howells module DOES NOT get stripped after being signed. This includes the 1666ea0b6dcfSDavid Howells debuginfo strip done by some packagers (such as rpmbuild) and 1667ea0b6dcfSDavid Howells inclusion into an initramfs that wants the module size reduced. 1668ea0b6dcfSDavid Howells 1669106a4ee2SRusty Russellconfig MODULE_SIG_FORCE 1670106a4ee2SRusty Russell bool "Require modules to be validly signed" 1671106a4ee2SRusty Russell depends on MODULE_SIG 1672106a4ee2SRusty Russell help 1673106a4ee2SRusty Russell Reject unsigned modules or signed modules for which we don't have a 1674106a4ee2SRusty Russell key. Without this, such modules will simply taint the kernel. 1675ea0b6dcfSDavid Howells 1676d9d8d7edSMichal Marekconfig MODULE_SIG_ALL 1677d9d8d7edSMichal Marek bool "Automatically sign all modules" 1678d9d8d7edSMichal Marek default y 1679d9d8d7edSMichal Marek depends on MODULE_SIG 1680d9d8d7edSMichal Marek help 1681d9d8d7edSMichal Marek Sign all modules during make modules_install. Without this option, 1682d9d8d7edSMichal Marek modules must be signed manually, using the scripts/sign-file tool. 1683d9d8d7edSMichal Marek 1684d9d8d7edSMichal Marekcomment "Do not forget to sign required modules with scripts/sign-file" 1685d9d8d7edSMichal Marek depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL 1686d9d8d7edSMichal Marek 1687ea0b6dcfSDavid Howellschoice 1688ea0b6dcfSDavid Howells prompt "Which hash algorithm should modules be signed with?" 1689ea0b6dcfSDavid Howells depends on MODULE_SIG 1690ea0b6dcfSDavid Howells help 1691ea0b6dcfSDavid Howells This determines which sort of hashing algorithm will be used during 1692ea0b6dcfSDavid Howells signature generation. This algorithm _must_ be built into the kernel 1693ea0b6dcfSDavid Howells directly so that signature verification can take place. It is not 1694ea0b6dcfSDavid Howells possible to load a signed module containing the algorithm to check 1695ea0b6dcfSDavid Howells the signature on that module. 1696ea0b6dcfSDavid Howells 1697ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA1 1698ea0b6dcfSDavid Howells bool "Sign modules with SHA-1" 1699ea0b6dcfSDavid Howells select CRYPTO_SHA1 1700ea0b6dcfSDavid Howells 1701ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA224 1702ea0b6dcfSDavid Howells bool "Sign modules with SHA-224" 1703ea0b6dcfSDavid Howells select CRYPTO_SHA256 1704ea0b6dcfSDavid Howells 1705ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA256 1706ea0b6dcfSDavid Howells bool "Sign modules with SHA-256" 1707ea0b6dcfSDavid Howells select CRYPTO_SHA256 1708ea0b6dcfSDavid Howells 1709ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA384 1710ea0b6dcfSDavid Howells bool "Sign modules with SHA-384" 1711ea0b6dcfSDavid Howells select CRYPTO_SHA512 1712ea0b6dcfSDavid Howells 1713ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA512 1714ea0b6dcfSDavid Howells bool "Sign modules with SHA-512" 1715ea0b6dcfSDavid Howells select CRYPTO_SHA512 1716ea0b6dcfSDavid Howells 1717ea0b6dcfSDavid Howellsendchoice 1718ea0b6dcfSDavid Howells 171922753674SMichal Marekconfig MODULE_SIG_HASH 172022753674SMichal Marek string 172122753674SMichal Marek depends on MODULE_SIG 172222753674SMichal Marek default "sha1" if MODULE_SIG_SHA1 172322753674SMichal Marek default "sha224" if MODULE_SIG_SHA224 172422753674SMichal Marek default "sha256" if MODULE_SIG_SHA256 172522753674SMichal Marek default "sha384" if MODULE_SIG_SHA384 172622753674SMichal Marek default "sha512" if MODULE_SIG_SHA512 172722753674SMichal Marek 17280b0de144SRobert P. J. Dayendif # MODULES 17290b0de144SRobert P. J. Day 173098a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 173198a79d6aSRusty Russell bool 173298a79d6aSRusty Russell help 17335f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 17345f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 173598a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 173698a79d6aSRusty Russell it was better to provide this option than to break all the archs 1737692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 173898a79d6aSRusty Russell 17391da177e4SLinus Torvaldsconfig STOP_MACHINE 17401da177e4SLinus Torvalds bool 17411da177e4SLinus Torvalds default y 17421da177e4SLinus Torvalds depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 17431da177e4SLinus Torvalds help 17441da177e4SLinus Torvalds Need stop_machine() primitive. 17453a65dfe8SJens Axboe 17463a65dfe8SJens Axboesource "block/Kconfig" 1747e98c3202SAvi Kivity 1748e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 1749e98c3202SAvi Kivity bool 1750e260be67SPaul E. McKenney 175116295becSSteffen Klassertconfig PADATA 175216295becSSteffen Klassert depends on SMP 175316295becSSteffen Klassert bool 175416295becSSteffen Klassert 1755754b7b63SAndi Kleen# Can be selected by architectures with broken toolchains 1756754b7b63SAndi Kleen# that get confused by correct const<->read_only section 1757754b7b63SAndi Kleen# mappings 1758754b7b63SAndi Kleenconfig BROKEN_RODATA 1759754b7b63SAndi Kleen bool 1760754b7b63SAndi Kleen 17614520c6a4SDavid Howellsconfig ASN1 17624520c6a4SDavid Howells tristate 17634520c6a4SDavid Howells help 17644520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 17654520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 17664520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 17674520c6a4SDavid Howells functions to call on what tags. 17684520c6a4SDavid Howells 17696beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 1770