180daa560SRoman Zippelconfig ARCH 280daa560SRoman Zippel string 380daa560SRoman Zippel option env="ARCH" 480daa560SRoman Zippel 580daa560SRoman Zippelconfig KERNELVERSION 680daa560SRoman Zippel string 780daa560SRoman Zippel option env="KERNELVERSION" 880daa560SRoman Zippel 9face4374SRoman Zippelconfig DEFCONFIG_LIST 10face4374SRoman Zippel string 11b2670eacSPaolo 'Blaisorblade' Giarrusso depends on !UML 12face4374SRoman Zippel option defconfig_list 13face4374SRoman Zippel default "/lib/modules/$UNAME_RELEASE/.config" 14face4374SRoman Zippel default "/etc/kernel-config" 15face4374SRoman Zippel default "/boot/config-$UNAME_RELEASE" 1673531905SSam Ravnborg default "$ARCH_DEFCONFIG" 17face4374SRoman Zippel default "arch/$ARCH/defconfig" 18face4374SRoman Zippel 19b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 20b99b87f7SPeter Oberparleiter bool 21b99b87f7SPeter Oberparleiter depends on !UML 22b99b87f7SPeter Oberparleiter 23e360adbeSPeter Zijlstraconfig HAVE_IRQ_WORK 24e360adbeSPeter Zijlstra bool 25e360adbeSPeter Zijlstra 26e360adbeSPeter Zijlstraconfig IRQ_WORK 27e360adbeSPeter Zijlstra bool 28e360adbeSPeter Zijlstra depends on HAVE_IRQ_WORK 29e360adbeSPeter Zijlstra 301dbdc6f1SDavid Daneyconfig BUILDTIME_EXTABLE_SORT 311dbdc6f1SDavid Daney bool 321dbdc6f1SDavid Daney 33ff0cfc66SAl Boldimenu "General setup" 341da177e4SLinus Torvalds 351da177e4SLinus Torvaldsconfig EXPERIMENTAL 361da177e4SLinus Torvalds bool "Prompt for development and/or incomplete code/drivers" 371da177e4SLinus Torvalds ---help--- 381da177e4SLinus Torvalds Some of the various things that Linux supports (such as network 391da177e4SLinus Torvalds drivers, file systems, network protocols, etc.) can be in a state 401da177e4SLinus Torvalds of development where the functionality, stability, or the level of 411da177e4SLinus Torvalds testing is not yet high enough for general use. This is usually 421da177e4SLinus Torvalds known as the "alpha-test" phase among developers. If a feature is 431da177e4SLinus Torvalds currently in alpha-test, then the developers usually discourage 441da177e4SLinus Torvalds uninformed widespread use of this feature by the general public to 451da177e4SLinus Torvalds avoid "Why doesn't this work?" type mail messages. However, active 461da177e4SLinus Torvalds testing and use of these systems is welcomed. Just be aware that it 471da177e4SLinus Torvalds may not meet the normal level of reliability or it may fail to work 481da177e4SLinus Torvalds in some special cases. Detailed bug reports from people familiar 491da177e4SLinus Torvalds with the kernel internals are usually welcomed by the developers 501da177e4SLinus Torvalds (before submitting bug reports, please read the documents 511da177e4SLinus Torvalds <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 521da177e4SLinus Torvalds <file:Documentation/BUG-HUNTING>, and 531da177e4SLinus Torvalds <file:Documentation/oops-tracing.txt> in the kernel source). 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds This option will also make obsoleted drivers available. These are 561da177e4SLinus Torvalds drivers that have been replaced by something else, and/or are 571da177e4SLinus Torvalds scheduled to be removed in a future kernel release. 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds Unless you intend to help test and develop a feature or driver that 601da177e4SLinus Torvalds falls into this category, or you have a situation that requires 611da177e4SLinus Torvalds using these features, you should probably say N here, which will 621da177e4SLinus Torvalds cause the configurator to present you with fewer choices. If 631da177e4SLinus Torvalds you say Y here, you will be offered the choice of using features or 641da177e4SLinus Torvalds drivers that are currently considered to be in the alpha-test phase. 651da177e4SLinus Torvalds 661da177e4SLinus Torvaldsconfig BROKEN 671da177e4SLinus Torvalds bool 681da177e4SLinus Torvalds 691da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 701da177e4SLinus Torvalds bool 711da177e4SLinus Torvalds depends on BROKEN || !SMP 721da177e4SLinus Torvalds default y 731da177e4SLinus Torvalds 741da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 751da177e4SLinus Torvalds int 76dd673bcaSAdrian Bunk default 32 if !UML 77dd673bcaSAdrian Bunk default 128 if UML 781da177e4SLinus Torvalds help 7934ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 8034ad92c2SRandy Dunlap variables passed to init from the kernel command line. 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds 8384336466SRoland McGrathconfig CROSS_COMPILE 8484336466SRoland McGrath string "Cross-compiler tool prefix" 8584336466SRoland McGrath help 8684336466SRoland McGrath Same as running 'make CROSS_COMPILE=prefix-' but stored for 8784336466SRoland McGrath default make runs in this kernel build directory. You don't 8884336466SRoland McGrath need to set this unless you want the configured kernel build 8984336466SRoland McGrath directory to select the cross-compiler automatically. 9084336466SRoland McGrath 911da177e4SLinus Torvaldsconfig LOCALVERSION 921da177e4SLinus Torvalds string "Local version - append to kernel release" 931da177e4SLinus Torvalds help 941da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 951da177e4SLinus Torvalds This will show up when you type uname, for example. 961da177e4SLinus Torvalds The string you set here will be appended after the contents of 971da177e4SLinus Torvalds any files with a filename matching localversion* in your 981da177e4SLinus Torvalds object and source tree, in that order. Your total string can 991da177e4SLinus Torvalds be a maximum of 64 characters. 1001da177e4SLinus Torvalds 101aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 102aaebf433SRyan Anderson bool "Automatically append version information to the version string" 103aaebf433SRyan Anderson default y 104aaebf433SRyan Anderson help 105aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 1066e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 1076e5a5420SRobert P. J. Day top of tree revision. 108aaebf433SRyan Anderson 109aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 1106e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 111aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 1126e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 113aaebf433SRyan Anderson 1146e5a5420SRobert P. J. Day (The actual string used here is the first eight characters produced 1156e5a5420SRobert P. J. Day by running the command: 1166e5a5420SRobert P. J. Day 1176e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 1186e5a5420SRobert P. J. Day 1196e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 120aaebf433SRyan Anderson 1212e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 1222e9f3bddSH. Peter Anvin bool 1232e9f3bddSH. Peter Anvin 1242e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 1252e9f3bddSH. Peter Anvin bool 1262e9f3bddSH. Peter Anvin 1272e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 1282e9f3bddSH. Peter Anvin bool 1292e9f3bddSH. Peter Anvin 1303ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 1313ebe1243SLasse Collin bool 1323ebe1243SLasse Collin 1337dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 1347dd65febSAlbin Tonnerre bool 1357dd65febSAlbin Tonnerre 13630d65dbfSAlain Knaffchoice 13730d65dbfSAlain Knaff prompt "Kernel compression mode" 13830d65dbfSAlain Knaff default KERNEL_GZIP 1393ebe1243SLasse Collin depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO 14030d65dbfSAlain Knaff help 14130d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 14230d65dbfSAlain Knaff Several compression algorithms are available, which differ 14330d65dbfSAlain Knaff in efficiency, compression and decompression speed. 14430d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 14530d65dbfSAlain Knaff Decompression speed is relevant at each boot. 14630d65dbfSAlain Knaff 14730d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 14830d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 14930d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 15030d65dbfSAlain Knaff supplied by Christian Ludwig) 15130d65dbfSAlain Knaff 15230d65dbfSAlain Knaff High compression options are mostly useful for users, who 15330d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 15430d65dbfSAlain Knaff size matters less. 15530d65dbfSAlain Knaff 15630d65dbfSAlain Knaff If in doubt, select 'gzip' 15730d65dbfSAlain Knaff 15830d65dbfSAlain Knaffconfig KERNEL_GZIP 15930d65dbfSAlain Knaff bool "Gzip" 1602e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 16130d65dbfSAlain Knaff help 1627dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 1637dd65febSAlbin Tonnerre between compression ratio and decompression speed. 16430d65dbfSAlain Knaff 16530d65dbfSAlain Knaffconfig KERNEL_BZIP2 16630d65dbfSAlain Knaff bool "Bzip2" 1672e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 16830d65dbfSAlain Knaff help 16930d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 1700a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 1712e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 1722e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 1732e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 17430d65dbfSAlain Knaff 17530d65dbfSAlain Knaffconfig KERNEL_LZMA 17630d65dbfSAlain Knaff bool "LZMA" 1772e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 17830d65dbfSAlain Knaff help 1790a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 1800a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 1810a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 18230d65dbfSAlain Knaff 1833ebe1243SLasse Collinconfig KERNEL_XZ 1843ebe1243SLasse Collin bool "XZ" 1853ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 1863ebe1243SLasse Collin help 1873ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 1883ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 1893ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 1903ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 1913ebe1243SLasse Collin filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ 1923ebe1243SLasse Collin will create a few percent smaller kernel than plain LZMA. 1933ebe1243SLasse Collin 1943ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 1953ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 1963ebe1243SLasse Collin and LZO. Compression is slow. 1973ebe1243SLasse Collin 1987dd65febSAlbin Tonnerreconfig KERNEL_LZO 1997dd65febSAlbin Tonnerre bool "LZO" 2007dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 2017dd65febSAlbin Tonnerre help 2020a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 203681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 2047dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 2057dd65febSAlbin Tonnerre 20630d65dbfSAlain Knaffendchoice 20730d65dbfSAlain Knaff 208bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 209bd5dc17bSJosh Triplett string "Default hostname" 210bd5dc17bSJosh Triplett default "(none)" 211bd5dc17bSJosh Triplett help 212bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 213bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 214bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 215bd5dc17bSJosh Triplett system more usable with less configuration. 216bd5dc17bSJosh Triplett 2171da177e4SLinus Torvaldsconfig SWAP 2181da177e4SLinus Torvalds bool "Support for paging of anonymous memory (swap)" 2199361401eSDavid Howells depends on MMU && BLOCK 2201da177e4SLinus Torvalds default y 2211da177e4SLinus Torvalds help 2221da177e4SLinus Torvalds This option allows you to choose whether you want to have support 2231da177e4SLinus Torvalds for so called swap devices or swap files in your kernel that are 2241da177e4SLinus Torvalds used to provide more virtual memory than the actual RAM present 2251da177e4SLinus Torvalds in your computer. If unsure say Y. 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvaldsconfig SYSVIPC 2281da177e4SLinus Torvalds bool "System V IPC" 2291da177e4SLinus Torvalds ---help--- 2301da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 2311da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 2321da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 2331da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 2341da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 2351da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 2361da177e4SLinus Torvalds you'll need to say Y here. 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 2391da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 2401da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 2411da177e4SLinus Torvalds 242a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 243a5494dcdSEric W. Biederman bool 244a5494dcdSEric W. Biederman depends on SYSVIPC 245a5494dcdSEric W. Biederman depends on SYSCTL 246a5494dcdSEric W. Biederman default y 247a5494dcdSEric W. Biederman 2481da177e4SLinus Torvaldsconfig POSIX_MQUEUE 2491da177e4SLinus Torvalds bool "POSIX Message Queues" 2501da177e4SLinus Torvalds depends on NET && EXPERIMENTAL 2511da177e4SLinus Torvalds ---help--- 2521da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 2531da177e4SLinus Torvalds queues every message has a priority which decides about succession 2541da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 2551da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 256b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 2591da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 2601da177e4SLinus Torvalds operations on message queues. 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds If unsure, say Y. 2631da177e4SLinus Torvalds 264bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 265bdc8e5f8SSerge E. Hallyn bool 266bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 267bdc8e5f8SSerge E. Hallyn depends on SYSCTL 268bdc8e5f8SSerge E. Hallyn default y 269bdc8e5f8SSerge E. Hallyn 2701da177e4SLinus Torvaldsconfig BSD_PROCESS_ACCT 2711da177e4SLinus Torvalds bool "BSD Process Accounting" 2721da177e4SLinus Torvalds help 2731da177e4SLinus Torvalds If you say Y here, a user level program will be able to instruct the 2741da177e4SLinus Torvalds kernel (via a special system call) to write process accounting 2751da177e4SLinus Torvalds information to a file: whenever a process exits, information about 2761da177e4SLinus Torvalds that process will be appended to the file by the kernel. The 2771da177e4SLinus Torvalds information includes things such as creation time, owning user, 2781da177e4SLinus Torvalds command name, memory usage, controlling terminal etc. (the complete 2791da177e4SLinus Torvalds list is in the struct acct in <file:include/linux/acct.h>). It is 2801da177e4SLinus Torvalds up to the user level program to do useful things with this 2811da177e4SLinus Torvalds information. This is generally a good idea, so say Y. 2821da177e4SLinus Torvalds 2831da177e4SLinus Torvaldsconfig BSD_PROCESS_ACCT_V3 2841da177e4SLinus Torvalds bool "BSD Process Accounting version 3 file format" 2851da177e4SLinus Torvalds depends on BSD_PROCESS_ACCT 2861da177e4SLinus Torvalds default n 2871da177e4SLinus Torvalds help 2881da177e4SLinus Torvalds If you say Y here, the process accounting information is written 2891da177e4SLinus Torvalds in a new file format that also logs the process IDs of each 2901da177e4SLinus Torvalds process and it's parent. Note that this file format is incompatible 2911da177e4SLinus Torvalds with previous v0/v1/v2 file formats, so you will need updated tools 2921da177e4SLinus Torvalds for processing it. A preliminary version of these tools is available 29337a4c940SS.Çağlar Onur at <http://www.gnu.org/software/acct/>. 2941da177e4SLinus Torvalds 295990d6c2dSAneesh Kumar K.Vconfig FHANDLE 296990d6c2dSAneesh Kumar K.V bool "open by fhandle syscalls" 297990d6c2dSAneesh Kumar K.V select EXPORTFS 298990d6c2dSAneesh Kumar K.V help 299990d6c2dSAneesh Kumar K.V If you say Y here, a user level program will be able to map 300990d6c2dSAneesh Kumar K.V file names to handle and then later use the handle for 301990d6c2dSAneesh Kumar K.V different file system operations. This is useful in implementing 302990d6c2dSAneesh Kumar K.V userspace file servers, which now track files using handles instead 303990d6c2dSAneesh Kumar K.V of names. The handle would remain the same even if file names 304990d6c2dSAneesh Kumar K.V get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 305990d6c2dSAneesh Kumar K.V syscalls. 306990d6c2dSAneesh Kumar K.V 307c757249aSShailabh Nagarconfig TASKSTATS 308c757249aSShailabh Nagar bool "Export task/process statistics through netlink (EXPERIMENTAL)" 309c757249aSShailabh Nagar depends on NET 310c757249aSShailabh Nagar default n 311c757249aSShailabh Nagar help 312c757249aSShailabh Nagar Export selected statistics for tasks/processes through the 313c757249aSShailabh Nagar generic netlink interface. Unlike BSD process accounting, the 314c757249aSShailabh Nagar statistics are available during the lifetime of tasks/processes as 315c757249aSShailabh Nagar responses to commands. Like BSD accounting, they are sent to user 316c757249aSShailabh Nagar space on task exit. 317c757249aSShailabh Nagar 318c757249aSShailabh Nagar Say N if unsure. 319c757249aSShailabh Nagar 320ca74e92bSShailabh Nagarconfig TASK_DELAY_ACCT 321ca74e92bSShailabh Nagar bool "Enable per-task delay accounting (EXPERIMENTAL)" 3226f44993fSShailabh Nagar depends on TASKSTATS 323ca74e92bSShailabh Nagar help 324ca74e92bSShailabh Nagar Collect information on time spent by a task waiting for system 325ca74e92bSShailabh Nagar resources like cpu, synchronous block I/O completion and swapping 326ca74e92bSShailabh Nagar in pages. Such statistics can help in setting a task's priorities 327ca74e92bSShailabh Nagar relative to other tasks for cpu, io, rss limits etc. 328ca74e92bSShailabh Nagar 329ca74e92bSShailabh Nagar Say N if unsure. 330ca74e92bSShailabh Nagar 33118f705f4SAlexey Dobriyanconfig TASK_XACCT 33218f705f4SAlexey Dobriyan bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 33318f705f4SAlexey Dobriyan depends on TASKSTATS 33418f705f4SAlexey Dobriyan help 33518f705f4SAlexey Dobriyan Collect extended task accounting data and send the data 33618f705f4SAlexey Dobriyan to userland for processing over the taskstats interface. 33718f705f4SAlexey Dobriyan 33818f705f4SAlexey Dobriyan Say N if unsure. 33918f705f4SAlexey Dobriyan 34018f705f4SAlexey Dobriyanconfig TASK_IO_ACCOUNTING 34118f705f4SAlexey Dobriyan bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 34218f705f4SAlexey Dobriyan depends on TASK_XACCT 34318f705f4SAlexey Dobriyan help 34418f705f4SAlexey Dobriyan Collect information on the number of bytes of storage I/O which this 34518f705f4SAlexey Dobriyan task has caused. 34618f705f4SAlexey Dobriyan 34718f705f4SAlexey Dobriyan Say N if unsure. 34818f705f4SAlexey Dobriyan 3491da177e4SLinus Torvaldsconfig AUDIT 3501da177e4SLinus Torvalds bool "Auditing support" 351804a6a49SChris Wright depends on NET 3521da177e4SLinus Torvalds help 3531da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 3541da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 3551da177e4SLinus Torvalds logging of avc messages output). Does not do system-call 3561da177e4SLinus Torvalds auditing without CONFIG_AUDITSYSCALL. 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvaldsconfig AUDITSYSCALL 3591da177e4SLinus Torvalds bool "Enable system-call auditing support" 3608f827a14SWill Deacon depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) 3611da177e4SLinus Torvalds default y if SECURITY_SELINUX 3621da177e4SLinus Torvalds help 3631da177e4SLinus Torvalds Enable low-overhead system-call auditing infrastructure that 3641da177e4SLinus Torvalds can be used independently or with another kernel subsystem, 36567640b60SEric Paris such as SELinux. 3661da177e4SLinus Torvalds 367939a67fcSEric Parisconfig AUDIT_WATCH 368939a67fcSEric Paris def_bool y 369939a67fcSEric Paris depends on AUDITSYSCALL 370939a67fcSEric Paris select FSNOTIFY 3711da177e4SLinus Torvalds 37274c3cbe3SAl Viroconfig AUDIT_TREE 37374c3cbe3SAl Viro def_bool y 37463c882a0SEric Paris depends on AUDITSYSCALL 37528a3a7ebSEric Paris select FSNOTIFY 37674c3cbe3SAl Viro 377633b4545SEric Parisconfig AUDIT_LOGINUID_IMMUTABLE 378633b4545SEric Paris bool "Make audit loginuid immutable" 379633b4545SEric Paris depends on AUDIT 380633b4545SEric Paris help 381f429ee3bSLinus Torvalds The config option toggles if a task setting its loginuid requires 382633b4545SEric Paris CAP_SYS_AUDITCONTROL or if that task should require no special permissions 383633b4545SEric Paris but should instead only allow setting its loginuid if it was never 384633b4545SEric Paris previously set. On systems which use systemd or a similar central 385633b4545SEric Paris process to restart login services this should be set to true. On older 386633b4545SEric Paris systems in which an admin would typically have to directly stop and 387633b4545SEric Paris start processes this should be set to false. Setting this to true allows 388633b4545SEric Paris one to drop potentially dangerous capabilites from the login tasks, 389633b4545SEric Paris but may not be backwards compatible with older init systems. 390633b4545SEric Paris 391d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 392764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 393d9817ebeSThomas Gleixner 394c903ff83SMike Travismenu "RCU Subsystem" 395c903ff83SMike Travis 396c903ff83SMike Travischoice 397c903ff83SMike Travis prompt "RCU Implementation" 39831c9a24eSPaul E. McKenney default TREE_RCU 399c903ff83SMike Travis 400c903ff83SMike Travisconfig TREE_RCU 401c903ff83SMike Travis bool "Tree-based hierarchical RCU" 402687d7a96SPaul E. McKenney depends on !PREEMPT && SMP 403c903ff83SMike Travis help 404c903ff83SMike Travis This option selects the RCU implementation that is 405c903ff83SMike Travis designed for very large SMP system with hundreds or 406c17ef453SPaul E. McKenney thousands of CPUs. It also scales down nicely to 407c17ef453SPaul E. McKenney smaller systems. 408c903ff83SMike Travis 409f41d911fSPaul E. McKenneyconfig TREE_PREEMPT_RCU 410a57eb940SPaul E. McKenney bool "Preemptible tree-based hierarchical RCU" 4118008e129SPaul E. McKenney depends on PREEMPT && SMP 412f41d911fSPaul E. McKenney help 413f41d911fSPaul E. McKenney This option selects the RCU implementation that is 414f41d911fSPaul E. McKenney designed for very large SMP systems with hundreds or 415f41d911fSPaul E. McKenney thousands of CPUs, but for which real-time response 416bbe3eae8SPaul E. McKenney is also required. It also scales down nicely to 417bbe3eae8SPaul E. McKenney smaller systems. 418f41d911fSPaul E. McKenney 4199b1d82faSPaul E. McKenneyconfig TINY_RCU 4209b1d82faSPaul E. McKenney bool "UP-only small-memory-footprint RCU" 4218008e129SPaul E. McKenney depends on !PREEMPT && !SMP 4229b1d82faSPaul E. McKenney help 4239b1d82faSPaul E. McKenney This option selects the RCU implementation that is 4249b1d82faSPaul E. McKenney designed for UP systems from which real-time response 4259b1d82faSPaul E. McKenney is not required. This option greatly reduces the 4269b1d82faSPaul E. McKenney memory footprint of RCU. 4279b1d82faSPaul E. McKenney 428a57eb940SPaul E. McKenneyconfig TINY_PREEMPT_RCU 429a57eb940SPaul E. McKenney bool "Preemptible UP-only small-memory-footprint RCU" 4308008e129SPaul E. McKenney depends on PREEMPT && !SMP 431a57eb940SPaul E. McKenney help 432a57eb940SPaul E. McKenney This option selects the RCU implementation that is designed 433a57eb940SPaul E. McKenney for real-time UP systems. This option greatly reduces the 434a57eb940SPaul E. McKenney memory footprint of RCU. 435a57eb940SPaul E. McKenney 436c903ff83SMike Travisendchoice 437c903ff83SMike Travis 438a57eb940SPaul E. McKenneyconfig PREEMPT_RCU 439a57eb940SPaul E. McKenney def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) 440a57eb940SPaul E. McKenney help 441a57eb940SPaul E. McKenney This option enables preemptible-RCU code that is common between 442a57eb940SPaul E. McKenney the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. 443a57eb940SPaul E. McKenney 4442b1d5024SFrederic Weisbeckerconfig RCU_USER_QS 4452b1d5024SFrederic Weisbecker bool "Consider userspace as in RCU extended quiescent state" 4462b1d5024SFrederic Weisbecker depends on HAVE_RCU_USER_QS && SMP 4472b1d5024SFrederic Weisbecker help 4482b1d5024SFrederic Weisbecker This option sets hooks on kernel / userspace boundaries and 4492b1d5024SFrederic Weisbecker puts RCU in extended quiescent state when the CPU runs in 4502b1d5024SFrederic Weisbecker userspace. It means that when a CPU runs in userspace, it is 4512b1d5024SFrederic Weisbecker excluded from the global RCU state machine and thus doesn't 4522b1d5024SFrederic Weisbecker to keep the timer tick on for RCU. 4532b1d5024SFrederic Weisbecker 454*d677124bSFrederic Weisbecker Unless you want to hack and help the development of the full 455*d677124bSFrederic Weisbecker tickless feature, you shouldn't enable this option. It adds 456*d677124bSFrederic Weisbecker unnecessary overhead. 457*d677124bSFrederic Weisbecker 458*d677124bSFrederic Weisbecker If unsure say N 459*d677124bSFrederic Weisbecker 4601fd2b442SFrederic Weisbeckerconfig RCU_USER_QS_FORCE 4611fd2b442SFrederic Weisbecker bool "Force userspace extended QS by default" 4621fd2b442SFrederic Weisbecker depends on RCU_USER_QS 4631fd2b442SFrederic Weisbecker help 4641fd2b442SFrederic Weisbecker Set the hooks in user/kernel boundaries by default in order to 4651fd2b442SFrederic Weisbecker test this feature that treats userspace as an extended quiescent 4661fd2b442SFrederic Weisbecker state until we have a real user like a full adaptive nohz option. 4671fd2b442SFrederic Weisbecker 468*d677124bSFrederic Weisbecker Unless you want to hack and help the development of the full 469*d677124bSFrederic Weisbecker tickless feature, you shouldn't enable this option. It adds 470*d677124bSFrederic Weisbecker unnecessary overhead. 471*d677124bSFrederic Weisbecker 472*d677124bSFrederic Weisbecker If unsure say N 473*d677124bSFrederic Weisbecker 474c903ff83SMike Travisconfig RCU_FANOUT 475c903ff83SMike Travis int "Tree-based hierarchical RCU fanout value" 476c903ff83SMike Travis range 2 64 if 64BIT 477c903ff83SMike Travis range 2 32 if !64BIT 478f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 479c903ff83SMike Travis default 64 if 64BIT 480c903ff83SMike Travis default 32 if !64BIT 481c903ff83SMike Travis help 482c903ff83SMike Travis This option controls the fanout of hierarchical implementations 483c903ff83SMike Travis of RCU, allowing RCU to work efficiently on machines with 4844d87ffadSPaul E. McKenney large numbers of CPUs. This value must be at least the fourth 4854d87ffadSPaul E. McKenney root of NR_CPUS, which allows NR_CPUS to be insanely large. 4864d87ffadSPaul E. McKenney The default value of RCU_FANOUT should be used for production 4874d87ffadSPaul E. McKenney systems, but if you are stress-testing the RCU implementation 4884d87ffadSPaul E. McKenney itself, small RCU_FANOUT values allow you to test large-system 4894d87ffadSPaul E. McKenney code paths on small(er) systems. 490c903ff83SMike Travis 491c903ff83SMike Travis Select a specific number if testing RCU itself. 492c903ff83SMike Travis Take the default if unsure. 493c903ff83SMike Travis 4948932a63dSPaul E. McKenneyconfig RCU_FANOUT_LEAF 4958932a63dSPaul E. McKenney int "Tree-based hierarchical RCU leaf-level fanout value" 4968932a63dSPaul E. McKenney range 2 RCU_FANOUT if 64BIT 4978932a63dSPaul E. McKenney range 2 RCU_FANOUT if !64BIT 4988932a63dSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 4998932a63dSPaul E. McKenney default 16 5008932a63dSPaul E. McKenney help 5018932a63dSPaul E. McKenney This option controls the leaf-level fanout of hierarchical 5028932a63dSPaul E. McKenney implementations of RCU, and allows trading off cache misses 5038932a63dSPaul E. McKenney against lock contention. Systems that synchronize their 5048932a63dSPaul E. McKenney scheduling-clock interrupts for energy-efficiency reasons will 5058932a63dSPaul E. McKenney want the default because the smaller leaf-level fanout keeps 5068932a63dSPaul E. McKenney lock contention levels acceptably low. Very large systems 5078932a63dSPaul E. McKenney (hundreds or thousands of CPUs) will instead want to set this 5088932a63dSPaul E. McKenney value to the maximum value possible in order to reduce the 5098932a63dSPaul E. McKenney number of cache misses incurred during RCU's grace-period 5108932a63dSPaul E. McKenney initialization. These systems tend to run CPU-bound, and thus 5118932a63dSPaul E. McKenney are not helped by synchronized interrupts, and thus tend to 5128932a63dSPaul E. McKenney skew them, which reduces lock contention enough that large 5138932a63dSPaul E. McKenney leaf-level fanouts work well. 5148932a63dSPaul E. McKenney 5158932a63dSPaul E. McKenney Select a specific number if testing RCU itself. 5168932a63dSPaul E. McKenney 5178932a63dSPaul E. McKenney Select the maximum permissible value for large systems. 5188932a63dSPaul E. McKenney 5198932a63dSPaul E. McKenney Take the default if unsure. 5208932a63dSPaul E. McKenney 521c903ff83SMike Travisconfig RCU_FANOUT_EXACT 522c903ff83SMike Travis bool "Disable tree-based hierarchical RCU auto-balancing" 523f41d911fSPaul E. McKenney depends on TREE_RCU || TREE_PREEMPT_RCU 524c903ff83SMike Travis default n 525c903ff83SMike Travis help 526c903ff83SMike Travis This option forces use of the exact RCU_FANOUT value specified, 527c903ff83SMike Travis regardless of imbalances in the hierarchy. This is useful for 528c903ff83SMike Travis testing RCU itself, and might one day be useful on systems with 529c903ff83SMike Travis strong NUMA behavior. 530c903ff83SMike Travis 531c903ff83SMike Travis Without RCU_FANOUT_EXACT, the code will balance the hierarchy. 532c903ff83SMike Travis 533c903ff83SMike Travis Say N if unsure. 534c903ff83SMike Travis 5358bd93a2cSPaul E. McKenneyconfig RCU_FAST_NO_HZ 5368bd93a2cSPaul E. McKenney bool "Accelerate last non-dyntick-idle CPU's grace periods" 537b807fbffSPaul E. McKenney depends on NO_HZ && SMP 5388bd93a2cSPaul E. McKenney default n 5398bd93a2cSPaul E. McKenney help 5408bd93a2cSPaul E. McKenney This option causes RCU to attempt to accelerate grace periods 541b807fbffSPaul E. McKenney in order to allow CPUs to enter dynticks-idle state more 542b807fbffSPaul E. McKenney quickly. On the other hand, this option increases the overhead 543b807fbffSPaul E. McKenney of the dynticks-idle checking, particularly on systems with 544b807fbffSPaul E. McKenney large numbers of CPUs. 5458bd93a2cSPaul E. McKenney 5468bd93a2cSPaul E. McKenney Say Y if energy efficiency is critically important, particularly 5478bd93a2cSPaul E. McKenney if you have relatively few CPUs. 5488bd93a2cSPaul E. McKenney 5498bd93a2cSPaul E. McKenney Say N if you are unsure. 5508bd93a2cSPaul E. McKenney 551c903ff83SMike Travisconfig TREE_RCU_TRACE 552f41d911fSPaul E. McKenney def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) 553c903ff83SMike Travis select DEBUG_FS 554c903ff83SMike Travis help 555f41d911fSPaul E. McKenney This option provides tracing for the TREE_RCU and 556f41d911fSPaul E. McKenney TREE_PREEMPT_RCU implementations, permitting Makefile to 557f41d911fSPaul E. McKenney trivially select kernel/rcutree_trace.c. 558c903ff83SMike Travis 55924278d14SPaul E. McKenneyconfig RCU_BOOST 56024278d14SPaul E. McKenney bool "Enable RCU priority boosting" 56127f4d280SPaul E. McKenney depends on RT_MUTEXES && PREEMPT_RCU 56224278d14SPaul E. McKenney default n 56324278d14SPaul E. McKenney help 56424278d14SPaul E. McKenney This option boosts the priority of preempted RCU readers that 56524278d14SPaul E. McKenney block the current preemptible RCU grace period for too long. 56624278d14SPaul E. McKenney This option also prevents heavy loads from blocking RCU 56724278d14SPaul E. McKenney callback invocation for all flavors of RCU. 56824278d14SPaul E. McKenney 56924278d14SPaul E. McKenney Say Y here if you are working with real-time apps or heavy loads 57024278d14SPaul E. McKenney Say N here if you are unsure. 57124278d14SPaul E. McKenney 57224278d14SPaul E. McKenneyconfig RCU_BOOST_PRIO 57324278d14SPaul E. McKenney int "Real-time priority to boost RCU readers to" 57424278d14SPaul E. McKenney range 1 99 57524278d14SPaul E. McKenney depends on RCU_BOOST 57624278d14SPaul E. McKenney default 1 57724278d14SPaul E. McKenney help 578c9336643SPaul E. McKenney This option specifies the real-time priority to which long-term 579c9336643SPaul E. McKenney preempted RCU readers are to be boosted. If you are working 580c9336643SPaul E. McKenney with a real-time application that has one or more CPU-bound 581c9336643SPaul E. McKenney threads running at a real-time priority level, you should set 582c9336643SPaul E. McKenney RCU_BOOST_PRIO to a priority higher then the highest-priority 583c9336643SPaul E. McKenney real-time CPU-bound thread. The default RCU_BOOST_PRIO value 584c9336643SPaul E. McKenney of 1 is appropriate in the common case, which is real-time 585c9336643SPaul E. McKenney applications that do not have any CPU-bound threads. 586c9336643SPaul E. McKenney 587c9336643SPaul E. McKenney Some real-time applications might not have a single real-time 588c9336643SPaul E. McKenney thread that saturates a given CPU, but instead might have 589c9336643SPaul E. McKenney multiple real-time threads that, taken together, fully utilize 590c9336643SPaul E. McKenney that CPU. In this case, you should set RCU_BOOST_PRIO to 591c9336643SPaul E. McKenney a priority higher than the lowest-priority thread that is 592c9336643SPaul E. McKenney conspiring to prevent the CPU from running any non-real-time 593c9336643SPaul E. McKenney tasks. For example, if one thread at priority 10 and another 594c9336643SPaul E. McKenney thread at priority 5 are between themselves fully consuming 595c9336643SPaul E. McKenney the CPU time on a given CPU, then RCU_BOOST_PRIO should be 596c9336643SPaul E. McKenney set to priority 6 or higher. 59724278d14SPaul E. McKenney 59824278d14SPaul E. McKenney Specify the real-time priority, or take the default if unsure. 59924278d14SPaul E. McKenney 60024278d14SPaul E. McKenneyconfig RCU_BOOST_DELAY 60124278d14SPaul E. McKenney int "Milliseconds to delay boosting after RCU grace-period start" 60224278d14SPaul E. McKenney range 0 3000 60324278d14SPaul E. McKenney depends on RCU_BOOST 60424278d14SPaul E. McKenney default 500 60524278d14SPaul E. McKenney help 60624278d14SPaul E. McKenney This option specifies the time to wait after the beginning of 60724278d14SPaul E. McKenney a given grace period before priority-boosting preempted RCU 60824278d14SPaul E. McKenney readers blocking that grace period. Note that any RCU reader 60924278d14SPaul E. McKenney blocking an expedited RCU grace period is boosted immediately. 61024278d14SPaul E. McKenney 61124278d14SPaul E. McKenney Accept the default if unsure. 61224278d14SPaul E. McKenney 613c903ff83SMike Travisendmenu # "RCU Subsystem" 614c903ff83SMike Travis 6151da177e4SLinus Torvaldsconfig IKCONFIG 616f2443ab6SRoss Biro tristate "Kernel .config support" 6171da177e4SLinus Torvalds ---help--- 6181da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 6191da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 6201da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 6211da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 6221da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 6231da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 6241da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 6251da177e4SLinus Torvalds /proc/config.gz if enabled (below). 6261da177e4SLinus Torvalds 6271da177e4SLinus Torvaldsconfig IKCONFIG_PROC 6281da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 6291da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 6301da177e4SLinus Torvalds ---help--- 6311da177e4SLinus Torvalds This option enables access to the kernel configuration file 6321da177e4SLinus Torvalds through /proc/config.gz. 6331da177e4SLinus Torvalds 634794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 635794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 636794543a2SAlistair John Strachan range 12 21 637f17a32e9SAdrian Bunk default 17 638794543a2SAlistair John Strachan help 639794543a2SAlistair John Strachan Select kernel log buffer size as a power of 2. 640f17a32e9SAdrian Bunk Examples: 641f17a32e9SAdrian Bunk 17 => 128 KB 642f17a32e9SAdrian Bunk 16 => 64 KB 643f17a32e9SAdrian Bunk 15 => 32 KB 644f17a32e9SAdrian Bunk 14 => 16 KB 645794543a2SAlistair John Strachan 13 => 8 KB 646794543a2SAlistair John Strachan 12 => 4 KB 647794543a2SAlistair John Strachan 6485cdc38f9SKAMEZAWA Hiroyuki# 6495cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 6505cdc38f9SKAMEZAWA Hiroyuki# 6515cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 6525cdc38f9SKAMEZAWA Hiroyuki bool 6535cdc38f9SKAMEZAWA Hiroyuki 65423964d2dSLi Zefanmenuconfig CGROUPS 65523964d2dSLi Zefan boolean "Control Group support" 6560dea1168SKirill A. Shutemov depends on EVENTFD 657ddbcc7e8SPaul Menage help 65823964d2dSLi Zefan This option adds support for grouping sets of processes together, for 6595cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 6605cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 6615cdc38f9SKAMEZAWA Hiroyuki See 6625cdc38f9SKAMEZAWA Hiroyuki - Documentation/scheduler/sched-design-CFS.txt (CFS) 66345ce80fbSLi Zefan - Documentation/cgroups/ (features for grouping, isolation 66445ce80fbSLi Zefan and resource control) 665ddbcc7e8SPaul Menage 666ddbcc7e8SPaul Menage Say N if unsure. 667ddbcc7e8SPaul Menage 66823964d2dSLi Zefanif CGROUPS 66923964d2dSLi Zefan 670006cb992SPaul Menageconfig CGROUP_DEBUG 671006cb992SPaul Menage bool "Example debug cgroup subsystem" 672418d7d87SPaul Menage default n 673006cb992SPaul Menage help 674006cb992SPaul Menage This option enables a simple cgroup subsystem that 675006cb992SPaul Menage exports useful debugging information about the cgroups 67623964d2dSLi Zefan framework. 677006cb992SPaul Menage 67823964d2dSLi Zefan Say N if unsure. 679006cb992SPaul Menage 680dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER 68123964d2dSLi Zefan bool "Freezer cgroup subsystem" 682dc52ddc0SMatt Helsley help 683dc52ddc0SMatt Helsley Provides a way to freeze and unfreeze all tasks in a 684dc52ddc0SMatt Helsley cgroup. 685dc52ddc0SMatt Helsley 68608ce5f16SSerge E. Hallynconfig CGROUP_DEVICE 68708ce5f16SSerge E. Hallyn bool "Device controller for cgroups" 68808ce5f16SSerge E. Hallyn help 68908ce5f16SSerge E. Hallyn Provides a cgroup implementing whitelists for devices which 69008ce5f16SSerge E. Hallyn a process in the cgroup can mknod or open. 69108ce5f16SSerge E. Hallyn 6921da177e4SLinus Torvaldsconfig CPUSETS 6931da177e4SLinus Torvalds bool "Cpuset support" 6941da177e4SLinus Torvalds help 695d9fd8a6dSRandy Dunlap This option will let you create and manage CPUSETs which 6961da177e4SLinus Torvalds allow dynamically partitioning a system into sets of CPUs and 6971da177e4SLinus Torvalds Memory Nodes and assigning tasks to run only within those sets. 6981da177e4SLinus Torvalds This is primarily useful on large SMP or NUMA systems. 6991da177e4SLinus Torvalds 7001da177e4SLinus Torvalds Say N if unsure. 7011da177e4SLinus Torvalds 70223964d2dSLi Zefanconfig PROC_PID_CPUSET 70323964d2dSLi Zefan bool "Include legacy /proc/<pid>/cpuset file" 70423964d2dSLi Zefan depends on CPUSETS 70523964d2dSLi Zefan default y 70623964d2dSLi Zefan 707d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT 708d842de87SSrivatsa Vaddagiri bool "Simple CPU accounting cgroup subsystem" 709d842de87SSrivatsa Vaddagiri help 710d842de87SSrivatsa Vaddagiri Provides a simple Resource Controller for monitoring the 71123964d2dSLi Zefan total CPU consumed by the tasks in a cgroup. 712d842de87SSrivatsa Vaddagiri 713e552b661SPavel Emelianovconfig RESOURCE_COUNTERS 714e552b661SPavel Emelianov bool "Resource counters" 715e552b661SPavel Emelianov help 716e552b661SPavel Emelianov This option enables controller independent resource accounting 71723964d2dSLi Zefan infrastructure that works with cgroups. 718e552b661SPavel Emelianov 719c255a458SAndrew Mortonconfig MEMCG 72000f0b825SBalbir Singh bool "Memory Resource Controller for Control Groups" 72179ae9c29SDaniel Lezcano depends on RESOURCE_COUNTERS 722cf475ad2SBalbir Singh select MM_OWNER 72300f0b825SBalbir Singh help 72484ad6d70SKAMEZAWA Hiroyuki Provides a memory resource controller that manages both anonymous 72521acb9caSThadeu Lima de Souza Cascardo memory and page cache. (See Documentation/cgroups/memory.txt) 72600f0b825SBalbir Singh 72700f0b825SBalbir Singh Note that setting this option increases fixed memory overhead 72884ad6d70SKAMEZAWA Hiroyuki associated with each page of memory in the system. By this, 72984ad6d70SKAMEZAWA Hiroyuki 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory 73084ad6d70SKAMEZAWA Hiroyuki usage tracking struct at boot. Total amount of this is printed out 73184ad6d70SKAMEZAWA Hiroyuki at boot. 73200f0b825SBalbir Singh 73300f0b825SBalbir Singh Only enable when you're ok with these trade offs and really 73484ad6d70SKAMEZAWA Hiroyuki sure you need the memory resource controller. Even when you enable 73584ad6d70SKAMEZAWA Hiroyuki this, you can set "cgroup_disable=memory" at your boot option to 73684ad6d70SKAMEZAWA Hiroyuki disable memory resource controller and you can avoid overheads. 737c9d5409fSLi Zefan (and lose benefits of memory resource controller) 73800f0b825SBalbir Singh 739cf475ad2SBalbir Singh This config option also selects MM_OWNER config option, which 740cf475ad2SBalbir Singh could in turn add some fork/exit overhead. 741cf475ad2SBalbir Singh 742c255a458SAndrew Mortonconfig MEMCG_SWAP 74365e0e811SKAMEZAWA Hiroyuki bool "Memory Resource Controller Swap Extension" 744c255a458SAndrew Morton depends on MEMCG && SWAP 745c077719bSKAMEZAWA Hiroyuki help 746c077719bSKAMEZAWA Hiroyuki Add swap management feature to memory resource controller. When you 747c077719bSKAMEZAWA Hiroyuki enable this, you can limit mem+swap usage per cgroup. In other words, 748c077719bSKAMEZAWA Hiroyuki when you disable this, memory resource controller has no cares to 749c077719bSKAMEZAWA Hiroyuki usage of swap...a process can exhaust all of the swap. This extension 750c077719bSKAMEZAWA Hiroyuki is useful when you want to avoid exhaustion swap but this itself 751c077719bSKAMEZAWA Hiroyuki adds more overheads and consumes memory for remembering information. 752c077719bSKAMEZAWA Hiroyuki Especially if you use 32bit system or small memory system, please 753c077719bSKAMEZAWA Hiroyuki be careful about enabling this. When memory resource controller 754c077719bSKAMEZAWA Hiroyuki is disabled by boot option, this will be automatically disabled and 755c077719bSKAMEZAWA Hiroyuki there will be no overhead from this. Even when you set this config=y, 75600a66d29SWANG Cong if boot option "swapaccount=0" is set, swap will not be accounted. 757627991a2SKAMEZAWA Hiroyuki Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page 758627991a2SKAMEZAWA Hiroyuki size is 4096bytes, 512k per 1Gbytes of swap. 759c255a458SAndrew Mortonconfig MEMCG_SWAP_ENABLED 760a42c390cSMichal Hocko bool "Memory Resource Controller Swap Extension enabled by default" 761c255a458SAndrew Morton depends on MEMCG_SWAP 762a42c390cSMichal Hocko default y 763a42c390cSMichal Hocko help 764a42c390cSMichal Hocko Memory Resource Controller Swap Extension comes with its price in 765a42c390cSMichal Hocko a bigger memory consumption. General purpose distribution kernels 76643d547f9SJim Cromie which want to enable the feature but keep it disabled by default 767a42c390cSMichal Hocko and let the user enable it by swapaccount boot command line 768a42c390cSMichal Hocko parameter should have this option unselected. 769a42c390cSMichal Hocko For those who want to have the feature enabled by default should 770a42c390cSMichal Hocko select this option (if, for some reason, they need to disable it 77100a66d29SWANG Cong then swapaccount=0 does the trick). 772c255a458SAndrew Mortonconfig MEMCG_KMEM 773e5671dfaSGlauber Costa bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)" 774c255a458SAndrew Morton depends on MEMCG && EXPERIMENTAL 775e5671dfaSGlauber Costa default n 776e5671dfaSGlauber Costa help 777e5671dfaSGlauber Costa The Kernel Memory extension for Memory Resource Controller can limit 778e5671dfaSGlauber Costa the amount of memory used by kernel objects in the system. Those are 779e5671dfaSGlauber Costa fundamentally different from the entities handled by the standard 780e5671dfaSGlauber Costa Memory Controller, which are page-based, and can be swapped. Users of 781e5671dfaSGlauber Costa the kmem extension can use it to guarantee that no group of processes 782e5671dfaSGlauber Costa will ever exhaust kernel resources alone. 783c077719bSKAMEZAWA Hiroyuki 7842bc64a20SAneesh Kumar K.Vconfig CGROUP_HUGETLB 7852bc64a20SAneesh Kumar K.V bool "HugeTLB Resource Controller for Control Groups" 7862bc64a20SAneesh Kumar K.V depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL 7872bc64a20SAneesh Kumar K.V default n 7882bc64a20SAneesh Kumar K.V help 7892bc64a20SAneesh Kumar K.V Provides a cgroup Resource Controller for HugeTLB pages. 7902bc64a20SAneesh Kumar K.V When you enable this, you can put a per cgroup limit on HugeTLB usage. 7912bc64a20SAneesh Kumar K.V The limit is enforced during page fault. Since HugeTLB doesn't 7922bc64a20SAneesh Kumar K.V support page reclaim, enforcing the limit at page fault time implies 7932bc64a20SAneesh Kumar K.V that, the application will get SIGBUS signal if it tries to access 7942bc64a20SAneesh Kumar K.V HugeTLB pages beyond its limit. This requires the application to know 7952bc64a20SAneesh Kumar K.V beforehand how much HugeTLB pages it would require for its use. The 7962bc64a20SAneesh Kumar K.V control group is tracked in the third page lru pointer. This means 7972bc64a20SAneesh Kumar K.V that we cannot use the controller with huge page less than 3 pages. 7982bc64a20SAneesh Kumar K.V 799e5d1367fSStephane Eranianconfig CGROUP_PERF 800e5d1367fSStephane Eranian bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" 801e5d1367fSStephane Eranian depends on PERF_EVENTS && CGROUPS 802e5d1367fSStephane Eranian help 803e5d1367fSStephane Eranian This option extends the per-cpu mode to restrict monitoring to 8042d0f2520SLi Zefan threads which belong to the cgroup specified and run on the 805e5d1367fSStephane Eranian designated cpu. 806e5d1367fSStephane Eranian 807e5d1367fSStephane Eranian Say N if unsure. 808e5d1367fSStephane Eranian 8097c941438SDhaval Gianimenuconfig CGROUP_SCHED 8107c941438SDhaval Giani bool "Group CPU scheduler" 8117c941438SDhaval Giani default n 8127c941438SDhaval Giani help 8137c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 8147c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 8157c941438SDhaval Giani tasks. 8167c941438SDhaval Giani 8177c941438SDhaval Gianiif CGROUP_SCHED 8187c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 8197c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 8207c941438SDhaval Giani depends on CGROUP_SCHED 8217c941438SDhaval Giani default CGROUP_SCHED 8227c941438SDhaval Giani 823ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 824ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 825ab84d31eSPaul Turner depends on EXPERIMENTAL 826ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 827ab84d31eSPaul Turner default n 828ab84d31eSPaul Turner help 829ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 830ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 831ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 832ab84d31eSPaul Turner restriction. 833ab84d31eSPaul Turner See tip/Documentation/scheduler/sched-bwc.txt for more information. 834ab84d31eSPaul Turner 8357c941438SDhaval Gianiconfig RT_GROUP_SCHED 8367c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 8377c941438SDhaval Giani depends on EXPERIMENTAL 8387c941438SDhaval Giani depends on CGROUP_SCHED 8397c941438SDhaval Giani default n 8407c941438SDhaval Giani help 8417c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 84232bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 8437c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 8447c941438SDhaval Giani realtime bandwidth for them. 8457c941438SDhaval Giani See Documentation/scheduler/sched-rt-group.txt for more information. 8467c941438SDhaval Giani 8477c941438SDhaval Gianiendif #CGROUP_SCHED 8487c941438SDhaval Giani 849afc24d49SVivek Goyalconfig BLK_CGROUP 85032e380aeSTejun Heo bool "Block IO controller" 85179ae9c29SDaniel Lezcano depends on BLOCK 852afc24d49SVivek Goyal default n 853afc24d49SVivek Goyal ---help--- 854afc24d49SVivek Goyal Generic block IO controller cgroup interface. This is the common 855afc24d49SVivek Goyal cgroup interface which should be used by various IO controlling 856afc24d49SVivek Goyal policies. 857afc24d49SVivek Goyal 858afc24d49SVivek Goyal Currently, CFQ IO scheduler uses it to recognize task groups and 859afc24d49SVivek Goyal control disk bandwidth allocation (proportional time slice allocation) 860e43473b7SVivek Goyal to such task groups. It is also used by bio throttling logic in 861e43473b7SVivek Goyal block layer to implement upper limit in IO rates on a device. 862afc24d49SVivek Goyal 863afc24d49SVivek Goyal This option only enables generic Block IO controller infrastructure. 864e43473b7SVivek Goyal One needs to also enable actual IO controlling logic/policy. For 86579e2e759SMichael Witten enabling proportional weight division of disk bandwidth in CFQ, set 86679e2e759SMichael Witten CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 867c5e0591aSMichael Witten CONFIG_BLK_DEV_THROTTLING=y. 868afc24d49SVivek Goyal 869afc24d49SVivek Goyal See Documentation/cgroups/blkio-controller.txt for more information. 870afc24d49SVivek Goyal 871afc24d49SVivek Goyalconfig DEBUG_BLK_CGROUP 872afc24d49SVivek Goyal bool "Enable Block IO controller debugging" 873afc24d49SVivek Goyal depends on BLK_CGROUP 874afc24d49SVivek Goyal default n 875afc24d49SVivek Goyal ---help--- 876afc24d49SVivek Goyal Enable some debugging help. Currently it exports additional stat 877afc24d49SVivek Goyal files in a cgroup which can be useful for debugging. 878afc24d49SVivek Goyal 87923964d2dSLi Zefanendif # CGROUPS 880c077719bSKAMEZAWA Hiroyuki 881067bce1aSCyrill Gorcunovconfig CHECKPOINT_RESTORE 882067bce1aSCyrill Gorcunov bool "Checkpoint/restore support" if EXPERT 883067bce1aSCyrill Gorcunov default n 884067bce1aSCyrill Gorcunov help 885067bce1aSCyrill Gorcunov Enables additional kernel features in a sake of checkpoint/restore. 886067bce1aSCyrill Gorcunov In particular it adds auxiliary prctl codes to setup process text, 887067bce1aSCyrill Gorcunov data and heap segment sizes, and a few additional /proc filesystem 888067bce1aSCyrill Gorcunov entries. 889067bce1aSCyrill Gorcunov 890067bce1aSCyrill Gorcunov If unsure, say N here. 891067bce1aSCyrill Gorcunov 8928dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 8936a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 8946a108a14SDavid Rientjes default !EXPERT 895c5289a69SPavel Emelyanov help 896c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 897c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 898c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 899c5289a69SPavel Emelyanov different namespaces. 900c5289a69SPavel Emelyanov 9018dd2a82cSDaniel Lezcanoif NAMESPACES 9028dd2a82cSDaniel Lezcano 90358bfdd6dSPavel Emelyanovconfig UTS_NS 90458bfdd6dSPavel Emelyanov bool "UTS namespace" 90517a6d441SDaniel Lezcano default y 90658bfdd6dSPavel Emelyanov help 90758bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 90858bfdd6dSPavel Emelyanov uname() system call 90958bfdd6dSPavel Emelyanov 910ae5e1b22SPavel Emelyanovconfig IPC_NS 911ae5e1b22SPavel Emelyanov bool "IPC namespace" 9128dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 91317a6d441SDaniel Lezcano default y 914ae5e1b22SPavel Emelyanov help 915ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 916614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 917ae5e1b22SPavel Emelyanov 918aee16ce7SPavel Emelyanovconfig USER_NS 919aee16ce7SPavel Emelyanov bool "User namespace (EXPERIMENTAL)" 9208dd2a82cSDaniel Lezcano depends on EXPERIMENTAL 921e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 9225673a94cSEric W. Biederman select UIDGID_STRICT_TYPE_CHECKS 923e1c972b6SEric W. Biederman 9245673a94cSEric W. Biederman default n 925aee16ce7SPavel Emelyanov help 926aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 927aee16ce7SPavel Emelyanov to provide different user info for different servers. 928aee16ce7SPavel Emelyanov If unsure, say N. 929aee16ce7SPavel Emelyanov 93074bd59bbSPavel Emelyanovconfig PID_NS 9319bd38c2cSDaniel Lezcano bool "PID Namespaces" 93217a6d441SDaniel Lezcano default y 93374bd59bbSPavel Emelyanov help 93412d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 935692105b8SMatt LaPlante processes with the same pid as long as they are in different 93674bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 93774bd59bbSPavel Emelyanov 938d6eb633fSMatt Helsleyconfig NET_NS 939d6eb633fSMatt Helsley bool "Network namespace" 9408dd2a82cSDaniel Lezcano depends on NET 94117a6d441SDaniel Lezcano default y 942d6eb633fSMatt Helsley help 943d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 944d6eb633fSMatt Helsley of the network stack. 945d6eb633fSMatt Helsley 9468dd2a82cSDaniel Lezcanoendif # NAMESPACES 9478dd2a82cSDaniel Lezcano 948e1c972b6SEric W. Biedermanconfig UIDGID_CONVERTED 949e1c972b6SEric W. Biederman # True if all of the selected software conmponents are known 950e1c972b6SEric W. Biederman # to have uid_t and gid_t converted to kuid_t and kgid_t 951e1c972b6SEric W. Biederman # where appropriate and are otherwise safe to use with 952e1c972b6SEric W. Biederman # the user namespace. 953e1c972b6SEric W. Biederman bool 954e1c972b6SEric W. Biederman default y 955e1c972b6SEric W. Biederman 956e1c972b6SEric W. Biederman # List of kernel pieces that need user namespace work 957e1c972b6SEric W. Biederman # Features 958e1c972b6SEric W. Biederman depends on SYSVIPC = n 959e1c972b6SEric W. Biederman depends on IMA = n 960e1c972b6SEric W. Biederman depends on EVM = n 961e1c972b6SEric W. Biederman depends on KEYS = n 962e1c972b6SEric W. Biederman depends on AUDIT = n 963e1c972b6SEric W. Biederman depends on AUDITSYSCALL = n 964e1c972b6SEric W. Biederman depends on TASKSTATS = n 965e1c972b6SEric W. Biederman depends on TRACING = n 966e1c972b6SEric W. Biederman depends on FS_POSIX_ACL = n 967e1c972b6SEric W. Biederman depends on QUOTA = n 968e1c972b6SEric W. Biederman depends on QUOTACTL = n 969e1c972b6SEric W. Biederman depends on DEBUG_CREDENTIALS = n 970e1c972b6SEric W. Biederman depends on BSD_PROCESS_ACCT = n 971e1c972b6SEric W. Biederman depends on DRM = n 972e1c972b6SEric W. Biederman depends on PROC_EVENTS = n 973e1c972b6SEric W. Biederman 974e1c972b6SEric W. Biederman # Networking 975e1c972b6SEric W. Biederman depends on NET = n 976e1c972b6SEric W. Biederman depends on NET_9P = n 977e1c972b6SEric W. Biederman depends on IPX = n 978e1c972b6SEric W. Biederman depends on PHONET = n 979e1c972b6SEric W. Biederman depends on NET_CLS_FLOW = n 980e1c972b6SEric W. Biederman depends on NETFILTER_XT_MATCH_OWNER = n 981e1c972b6SEric W. Biederman depends on NETFILTER_XT_MATCH_RECENT = n 982e1c972b6SEric W. Biederman depends on NETFILTER_XT_TARGET_LOG = n 983e1c972b6SEric W. Biederman depends on NETFILTER_NETLINK_LOG = n 984e1c972b6SEric W. Biederman depends on INET = n 985e1c972b6SEric W. Biederman depends on IPV6 = n 986e1c972b6SEric W. Biederman depends on IP_SCTP = n 987e1c972b6SEric W. Biederman depends on AF_RXRPC = n 988e1c972b6SEric W. Biederman depends on LLC2 = n 989e1c972b6SEric W. Biederman depends on NET_KEY = n 990e1c972b6SEric W. Biederman depends on INET_DIAG = n 991e1c972b6SEric W. Biederman depends on DNS_RESOLVER = n 992e1c972b6SEric W. Biederman depends on AX25 = n 993e1c972b6SEric W. Biederman depends on ATALK = n 994e1c972b6SEric W. Biederman 995e1c972b6SEric W. Biederman # Filesystems 996e1c972b6SEric W. Biederman depends on USB_DEVICEFS = n 997e1c972b6SEric W. Biederman depends on USB_GADGETFS = n 998e1c972b6SEric W. Biederman depends on USB_FUNCTIONFS = n 999e1c972b6SEric W. Biederman depends on DEVTMPFS = n 1000e1c972b6SEric W. Biederman depends on XENFS = n 1001e1c972b6SEric W. Biederman 1002e1c972b6SEric W. Biederman depends on 9P_FS = n 1003e1c972b6SEric W. Biederman depends on ADFS_FS = n 1004e1c972b6SEric W. Biederman depends on AFFS_FS = n 1005e1c972b6SEric W. Biederman depends on AFS_FS = n 1006e1c972b6SEric W. Biederman depends on AUTOFS4_FS = n 1007e1c972b6SEric W. Biederman depends on BEFS_FS = n 1008e1c972b6SEric W. Biederman depends on BFS_FS = n 1009e1c972b6SEric W. Biederman depends on BTRFS_FS = n 1010e1c972b6SEric W. Biederman depends on CEPH_FS = n 1011e1c972b6SEric W. Biederman depends on CIFS = n 1012e1c972b6SEric W. Biederman depends on CODA_FS = n 1013e1c972b6SEric W. Biederman depends on CONFIGFS_FS = n 1014e1c972b6SEric W. Biederman depends on CRAMFS = n 1015e1c972b6SEric W. Biederman depends on DEBUG_FS = n 1016e1c972b6SEric W. Biederman depends on ECRYPT_FS = n 1017e1c972b6SEric W. Biederman depends on EFS_FS = n 1018e1c972b6SEric W. Biederman depends on EXOFS_FS = n 1019e1c972b6SEric W. Biederman depends on FAT_FS = n 1020e1c972b6SEric W. Biederman depends on FUSE_FS = n 1021e1c972b6SEric W. Biederman depends on GFS2_FS = n 1022e1c972b6SEric W. Biederman depends on HFS_FS = n 1023e1c972b6SEric W. Biederman depends on HFSPLUS_FS = n 1024e1c972b6SEric W. Biederman depends on HPFS_FS = n 1025e1c972b6SEric W. Biederman depends on HUGETLBFS = n 1026e1c972b6SEric W. Biederman depends on ISO9660_FS = n 1027e1c972b6SEric W. Biederman depends on JFFS2_FS = n 1028e1c972b6SEric W. Biederman depends on JFS_FS = n 1029e1c972b6SEric W. Biederman depends on LOGFS = n 1030e1c972b6SEric W. Biederman depends on MINIX_FS = n 1031e1c972b6SEric W. Biederman depends on NCP_FS = n 1032e1c972b6SEric W. Biederman depends on NFSD = n 1033e1c972b6SEric W. Biederman depends on NFS_FS = n 1034e1c972b6SEric W. Biederman depends on NILFS2_FS = n 1035e1c972b6SEric W. Biederman depends on NTFS_FS = n 1036e1c972b6SEric W. Biederman depends on OCFS2_FS = n 1037e1c972b6SEric W. Biederman depends on OMFS_FS = n 1038e1c972b6SEric W. Biederman depends on QNX4FS_FS = n 1039e1c972b6SEric W. Biederman depends on QNX6FS_FS = n 1040e1c972b6SEric W. Biederman depends on REISERFS_FS = n 1041e1c972b6SEric W. Biederman depends on SQUASHFS = n 1042e1c972b6SEric W. Biederman depends on SYSV_FS = n 1043e1c972b6SEric W. Biederman depends on UBIFS_FS = n 1044e1c972b6SEric W. Biederman depends on UDF_FS = n 1045e1c972b6SEric W. Biederman depends on UFS_FS = n 1046e1c972b6SEric W. Biederman depends on VXFS_FS = n 1047e1c972b6SEric W. Biederman depends on XFS_FS = n 1048e1c972b6SEric W. Biederman 1049e1c972b6SEric W. Biederman depends on !UML || HOSTFS = n 1050e1c972b6SEric W. Biederman 1051e1c972b6SEric W. Biederman # The rare drivers that won't build 1052e1c972b6SEric W. Biederman depends on AIRO = n 1053e1c972b6SEric W. Biederman depends on AIRO_CS = n 1054e1c972b6SEric W. Biederman depends on TUN = n 1055e1c972b6SEric W. Biederman depends on INFINIBAND_QIB = n 1056e1c972b6SEric W. Biederman depends on BLK_DEV_LOOP = n 1057e1c972b6SEric W. Biederman depends on ANDROID_BINDER_IPC = n 1058e1c972b6SEric W. Biederman 1059e1c972b6SEric W. Biederman # Security modules 1060e1c972b6SEric W. Biederman depends on SECURITY_TOMOYO = n 1061e1c972b6SEric W. Biederman depends on SECURITY_APPARMOR = n 1062e1c972b6SEric W. Biederman 10635673a94cSEric W. Biedermanconfig UIDGID_STRICT_TYPE_CHECKS 10645673a94cSEric W. Biederman bool "Require conversions between uid/gids and their internal representation" 1065e1c972b6SEric W. Biederman depends on UIDGID_CONVERTED 10665673a94cSEric W. Biederman default n 10675673a94cSEric W. Biederman help 10685673a94cSEric W. Biederman While the nececessary conversions are being added to all subsystems this option allows 10695673a94cSEric W. Biederman the code to continue to build for unconverted subsystems. 10705673a94cSEric W. Biederman 10715673a94cSEric W. Biederman Say Y here if you want the strict type checking enabled 10725673a94cSEric W. Biederman 10735091faa4SMike Galbraithconfig SCHED_AUTOGROUP 10745091faa4SMike Galbraith bool "Automatic process group scheduling" 10755091faa4SMike Galbraith select EVENTFD 10765091faa4SMike Galbraith select CGROUPS 10775091faa4SMike Galbraith select CGROUP_SCHED 10785091faa4SMike Galbraith select FAIR_GROUP_SCHED 10795091faa4SMike Galbraith help 10805091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 10815091faa4SMike Galbraith automatically creating and populating task groups. This separation 10825091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 10835091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 10845091faa4SMike Galbraith upon task session. 10855091faa4SMike Galbraith 10867af37becSDaniel Lezcanoconfig MM_OWNER 10877af37becSDaniel Lezcano bool 10887af37becSDaniel Lezcano 10897af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED 10905d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features to support old userspace tools" 10917af37becSDaniel Lezcano depends on SYSFS 10927af37becSDaniel Lezcano default n 10937af37becSDaniel Lezcano help 10947af37becSDaniel Lezcano This option adds code that switches the layout of the "block" class 10957af37becSDaniel Lezcano devices, to not show up in /sys/class/block/, but only in 10967af37becSDaniel Lezcano /sys/block/. 10977af37becSDaniel Lezcano 10987af37becSDaniel Lezcano This switch is only active when the sysfs.deprecated=1 boot option is 10997af37becSDaniel Lezcano passed or the SYSFS_DEPRECATED_V2 option is set. 11007af37becSDaniel Lezcano 11017af37becSDaniel Lezcano This option allows new kernels to run on old distributions and tools, 11027af37becSDaniel Lezcano which might get confused by /sys/class/block/. Since 2007/2008 all 11037af37becSDaniel Lezcano major distributions and tools handle this just fine. 11047af37becSDaniel Lezcano 11057af37becSDaniel Lezcano Recent distributions and userspace tools after 2009/2010 depend on 11067af37becSDaniel Lezcano the existence of /sys/class/block/, and will not work with this 11077af37becSDaniel Lezcano option enabled. 11087af37becSDaniel Lezcano 11097af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 11107af37becSDaniel Lezcano need to say Y here. 11117af37becSDaniel Lezcano 11127af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED_V2 11135d6a4ea5SFerenc Wagner bool "Enable deprecated sysfs features by default" 11147af37becSDaniel Lezcano default n 11157af37becSDaniel Lezcano depends on SYSFS 11167af37becSDaniel Lezcano depends on SYSFS_DEPRECATED 11177af37becSDaniel Lezcano help 11187af37becSDaniel Lezcano Enable deprecated sysfs by default. 11197af37becSDaniel Lezcano 11207af37becSDaniel Lezcano See the CONFIG_SYSFS_DEPRECATED option for more details about this 11217af37becSDaniel Lezcano option. 11227af37becSDaniel Lezcano 11237af37becSDaniel Lezcano Only if you are using a new kernel on an old distribution, you might 11247af37becSDaniel Lezcano need to say Y here. Even then, odds are you would not need it 11257af37becSDaniel Lezcano enabled, you can always pass the boot option if absolutely necessary. 11267af37becSDaniel Lezcano 11277af37becSDaniel Lezcanoconfig RELAY 11287af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 11297af37becSDaniel Lezcano help 11307af37becSDaniel Lezcano This option enables support for relay interface support in 11317af37becSDaniel Lezcano certain file systems (such as debugfs). 11327af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 11337af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 11347af37becSDaniel Lezcano user space. 11357af37becSDaniel Lezcano 11367af37becSDaniel Lezcano If unsure, say N. 11377af37becSDaniel Lezcano 1138f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1139f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1140f991633dSDimitri Gorokhovik depends on BROKEN || !FRV 1141f991633dSDimitri Gorokhovik help 1142f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1143f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1144f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1145f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 1146f991633dSDimitri Gorokhovik etc. See <file:Documentation/initrd.txt> for details. 1147f991633dSDimitri Gorokhovik 1148f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1149f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1150f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1151f991633dSDimitri Gorokhovik 1152f991633dSDimitri Gorokhovik If unsure say Y. 1153f991633dSDimitri Gorokhovik 1154c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1155c33df4eaSJean-Paul Saman 1156dbec4866SSam Ravnborgsource "usr/Kconfig" 1157dbec4866SSam Ravnborg 1158c33df4eaSJean-Paul Samanendif 1159c33df4eaSJean-Paul Saman 1160c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 116196fffeb4SIngo Molnar bool "Optimize for size" 1162c45b4f1fSLinus Torvalds help 1163c45b4f1fSLinus Torvalds Enabling this option will pass "-Os" instead of "-O2" to gcc 1164c45b4f1fSLinus Torvalds resulting in a smaller kernel. 1165c45b4f1fSLinus Torvalds 1166775a7229Sjkacur If unsure, say Y. 1167c45b4f1fSLinus Torvalds 11680847062aSRandy Dunlapconfig SYSCTL 11690847062aSRandy Dunlap bool 11700847062aSRandy Dunlap 1171b943c460SRandy Dunlapconfig ANON_INODES 1172b943c460SRandy Dunlap bool 1173b943c460SRandy Dunlap 11746a108a14SDavid Rientjesmenuconfig EXPERT 11756a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1176f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1177f505c553SJosh Triplett select DEBUG_KERNEL 11781da177e4SLinus Torvalds help 11791da177e4SLinus Torvalds This option allows certain base kernel options and settings 11801da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 11811da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 11821da177e4SLinus Torvalds Only use this if you really know what you are doing. 11831da177e4SLinus Torvalds 1184ae81f9e3SChuck Ebbertconfig UID16 11856a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 118609337f50SDavid S. Miller depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 1187ae81f9e3SChuck Ebbert default y 1188ae81f9e3SChuck Ebbert help 1189ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1190ae81f9e3SChuck Ebbert 1191b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL 11926a108a14SDavid Rientjes bool "Sysctl syscall support" if EXPERT 119326a7034bSEric W. Biederman depends on PROC_SYSCTL 1194c736de60SWANG Cong default n 1195b89a8171SEric W. Biederman select SYSCTL 1196b89a8171SEric W. Biederman ---help--- 119713bb7e37SEric W. Biederman sys_sysctl uses binary paths that have been found challenging 119813bb7e37SEric W. Biederman to properly maintain and use. The interface in /proc/sys 119913bb7e37SEric W. Biederman using paths with ascii names is now the primary path to this 120013bb7e37SEric W. Biederman information. 1201b89a8171SEric W. Biederman 120213bb7e37SEric W. Biederman Almost nothing using the binary sysctl interface so if you are 120313bb7e37SEric W. Biederman trying to save some space it is probably safe to disable this, 120413bb7e37SEric W. Biederman making your kernel marginally smaller. 1205b89a8171SEric W. Biederman 1206c736de60SWANG Cong If unsure say N here. 1207ae81f9e3SChuck Ebbert 12081da177e4SLinus Torvaldsconfig KALLSYMS 12096a108a14SDavid Rientjes bool "Load all symbols for debugging/ksymoops" if EXPERT 12101da177e4SLinus Torvalds default y 12111da177e4SLinus Torvalds help 12121da177e4SLinus Torvalds Say Y here to let the kernel print out symbolic crash information and 12131da177e4SLinus Torvalds symbolic stack backtraces. This increases the size of the kernel 12141da177e4SLinus Torvalds somewhat, as all symbols have to be loaded into the kernel image. 12151da177e4SLinus Torvalds 12161da177e4SLinus Torvaldsconfig KALLSYMS_ALL 12171da177e4SLinus Torvalds bool "Include all symbols in kallsyms" 12181da177e4SLinus Torvalds depends on DEBUG_KERNEL && KALLSYMS 12191da177e4SLinus Torvalds help 122071a83ec7SArtem Bityutskiy Normally kallsyms only contains the symbols of functions for nicer 122171a83ec7SArtem Bityutskiy OOPS messages and backtraces (i.e., symbols from the text and inittext 122271a83ec7SArtem Bityutskiy sections). This is sufficient for most cases. And only in very rare 122371a83ec7SArtem Bityutskiy cases (e.g., when a debugger is used) all symbols are required (e.g., 122471a83ec7SArtem Bityutskiy names of variables from the data sections, etc). 12251da177e4SLinus Torvalds 122671a83ec7SArtem Bityutskiy This option makes sure that all symbols are loaded into the kernel 122771a83ec7SArtem Bityutskiy image (i.e., symbols from all sections) in cost of increased kernel 122871a83ec7SArtem Bityutskiy size (depending on the kernel configuration, it may be 300KiB or 122971a83ec7SArtem Bityutskiy something like this). 12301da177e4SLinus Torvalds 123171a83ec7SArtem Bityutskiy Say N unless you really need all symbols. 1232d59745ceSMatt Mackall 1233712f47ceSGreg Kroah-Hartmanconfig HOTPLUG 12346a108a14SDavid Rientjes bool "Support for hot-pluggable devices" if EXPERT 1235712f47ceSGreg Kroah-Hartman default y 1236712f47ceSGreg Kroah-Hartman help 1237712f47ceSGreg Kroah-Hartman This option is provided for the case where no hotplug or uevent 1238712f47ceSGreg Kroah-Hartman capabilities is wanted by the kernel. You should only consider 1239712f47ceSGreg Kroah-Hartman disabling this option for embedded systems that do not use modules, a 1240712f47ceSGreg Kroah-Hartman dynamic /dev tree, or dynamic device discovery. Just say Y. 1241712f47ceSGreg Kroah-Hartman 1242d59745ceSMatt Mackallconfig PRINTK 1243d59745ceSMatt Mackall default y 12446a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 1245d59745ceSMatt Mackall help 1246d59745ceSMatt Mackall This option enables normal printk support. Removing it 1247d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1248d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1249d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1250d59745ceSMatt Mackall strongly discouraged. 1251d59745ceSMatt Mackall 1252c8538a7aSMatt Mackallconfig BUG 12536a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1254c8538a7aSMatt Mackall default y 1255c8538a7aSMatt Mackall help 1256c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1257c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1258c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1259c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1260c8538a7aSMatt Mackall Just say Y. 1261c8538a7aSMatt Mackall 1262708e9a79SMatt Mackallconfig ELF_CORE 1263708e9a79SMatt Mackall default y 12646a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1265708e9a79SMatt Mackall help 1266708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1267708e9a79SMatt Mackall 12688761f1abSRalf Baechle 1269e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 12706a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 12718761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 127215f304b6SRalf Baechle select I8253_LOCK 1273e5e1d3cbSStas Sergeev default y 1274e5e1d3cbSStas Sergeev help 1275e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1276e5e1d3cbSStas Sergeev support, saving some memory. 1277e5e1d3cbSStas Sergeev 12788761f1abSRalf Baechleconfig HAVE_PCSPKR_PLATFORM 12798761f1abSRalf Baechle bool 12808761f1abSRalf Baechle 12811da177e4SLinus Torvaldsconfig BASE_FULL 12821da177e4SLinus Torvalds default y 12836a108a14SDavid Rientjes bool "Enable full-sized data structures for core" if EXPERT 12841da177e4SLinus Torvalds help 12851da177e4SLinus Torvalds Disabling this option reduces the size of miscellaneous core 12861da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 12871da177e4SLinus Torvalds but may reduce performance. 12881da177e4SLinus Torvalds 12891da177e4SLinus Torvaldsconfig FUTEX 12906a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 12911da177e4SLinus Torvalds default y 129223f78d4aSIngo Molnar select RT_MUTEXES 12931da177e4SLinus Torvalds help 12941da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 12951da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 12961da177e4SLinus Torvalds run glibc-based applications correctly. 12971da177e4SLinus Torvalds 12981da177e4SLinus Torvaldsconfig EPOLL 12996a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 13001da177e4SLinus Torvalds default y 1301448e3ceeSAdrian Bunk select ANON_INODES 13021da177e4SLinus Torvalds help 13031da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 13041da177e4SLinus Torvalds support for epoll family of system calls. 13051da177e4SLinus Torvalds 1306fba2afaaSDavide Libenziconfig SIGNALFD 13076a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1308448e3ceeSAdrian Bunk select ANON_INODES 1309fba2afaaSDavide Libenzi default y 1310fba2afaaSDavide Libenzi help 1311fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1312fba2afaaSDavide Libenzi on a file descriptor. 1313fba2afaaSDavide Libenzi 1314fba2afaaSDavide Libenzi If unsure, say Y. 1315fba2afaaSDavide Libenzi 1316b215e283SDavide Libenziconfig TIMERFD 13176a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1318448e3ceeSAdrian Bunk select ANON_INODES 1319b215e283SDavide Libenzi default y 1320b215e283SDavide Libenzi help 1321b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1322b215e283SDavide Libenzi events on a file descriptor. 1323b215e283SDavide Libenzi 1324b215e283SDavide Libenzi If unsure, say Y. 1325b215e283SDavide Libenzi 1326e1ad7468SDavide Libenziconfig EVENTFD 13276a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1328448e3ceeSAdrian Bunk select ANON_INODES 1329e1ad7468SDavide Libenzi default y 1330e1ad7468SDavide Libenzi help 1331e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1332e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1333e1ad7468SDavide Libenzi 1334e1ad7468SDavide Libenzi If unsure, say Y. 1335e1ad7468SDavide Libenzi 13361da177e4SLinus Torvaldsconfig SHMEM 13376a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 13381da177e4SLinus Torvalds default y 13391da177e4SLinus Torvalds depends on MMU 13401da177e4SLinus Torvalds help 13411da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 13421da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 13431da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 13441da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 13451da177e4SLinus Torvalds which may be appropriate on small systems without swap. 13461da177e4SLinus Torvalds 1347ebf3f09cSThomas Petazzoniconfig AIO 13486a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1349ebf3f09cSThomas Petazzoni default y 1350ebf3f09cSThomas Petazzoni help 1351ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1352ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1353ebf3f09cSThomas Petazzoni this option saves about 7k. 1354ebf3f09cSThomas Petazzoni 13556befe5f6SRandy Dunlapconfig EMBEDDED 13566befe5f6SRandy Dunlap bool "Embedded system" 13576befe5f6SRandy Dunlap select EXPERT 13586befe5f6SRandy Dunlap help 13596befe5f6SRandy Dunlap This option should be enabled if compiling the kernel for 13606befe5f6SRandy Dunlap an embedded system so certain expert options are available 13616befe5f6SRandy Dunlap for configuration. 13626befe5f6SRandy Dunlap 1363cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 13640793a61dSThomas Gleixner bool 1365018df72dSMike Frysinger help 1366018df72dSMike Frysinger See tools/perf/design.txt for details. 13670793a61dSThomas Gleixner 1368906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 1369906010b2SPeter Zijlstra bool 1370906010b2SPeter Zijlstra help 1371906010b2SPeter Zijlstra See tools/perf/design.txt for details 1372906010b2SPeter Zijlstra 137357c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 13740793a61dSThomas Gleixner 1375cdd6c482SIngo Molnarconfig PERF_EVENTS 137657c0c15bSIngo Molnar bool "Kernel performance events and counters" 1377392d65a9SRobert Richter default y if PROFILING 1378cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 13794c59e467SIngo Molnar select ANON_INODES 1380e360adbeSPeter Zijlstra select IRQ_WORK 13810793a61dSThomas Gleixner help 138257c0c15bSIngo Molnar Enable kernel support for various performance events provided 138357c0c15bSIngo Molnar by software and hardware. 13840793a61dSThomas Gleixner 1385dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 138657c0c15bSIngo Molnar use of generic tracepoints. 138757c0c15bSIngo Molnar 138857c0c15bSIngo Molnar Most modern CPUs support performance events via performance 138957c0c15bSIngo Molnar counter registers. These registers count the number of certain 13900793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 13910793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 13920793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 13930793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 13940793a61dSThomas Gleixner used to profile the code that runs on that CPU. 13950793a61dSThomas Gleixner 139657c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 1397dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 139857c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 13990793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 14000793a61dSThomas Gleixner capabilities on top of those. 14010793a61dSThomas Gleixner 14020793a61dSThomas Gleixner Say Y if unsure. 14030793a61dSThomas Gleixner 1404906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 1405906010b2SPeter Zijlstra default n 1406906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 1407906010b2SPeter Zijlstra depends on PERF_EVENTS && DEBUG_KERNEL 1408906010b2SPeter Zijlstra select PERF_USE_VMALLOC 1409906010b2SPeter Zijlstra help 1410906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 1411906010b2SPeter Zijlstra 1412906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 1413906010b2SPeter Zijlstra that don't require it. 1414906010b2SPeter Zijlstra 1415906010b2SPeter Zijlstra Say N if unsure. 1416906010b2SPeter Zijlstra 14170793a61dSThomas Gleixnerendmenu 14180793a61dSThomas Gleixner 1419f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS 1420f8891e5eSChristoph Lameter default y 14216a108a14SDavid Rientjes bool "Enable VM event counters for /proc/vmstat" if EXPERT 1422f8891e5eSChristoph Lameter help 14232aea4fb6SPaul Jackson VM event counters are needed for event counts to be shown. 14242aea4fb6SPaul Jackson This option allows the disabling of the VM event counters 14256a108a14SDavid Rientjes on EXPERT systems. /proc/vmstat will only show page counts 14262aea4fb6SPaul Jackson if VM event counters are disabled. 1427f8891e5eSChristoph Lameter 14283d137310SThomas Petazzoniconfig PCI_QUIRKS 14293d137310SThomas Petazzoni default y 14306a108a14SDavid Rientjes bool "Enable PCI quirk workarounds" if EXPERT 143161cfc7e4SGeert Uytterhoeven depends on PCI 14323d137310SThomas Petazzoni help 14333d137310SThomas Petazzoni This enables workarounds for various PCI chipset 14343d137310SThomas Petazzoni bugs/quirks. Disable this only if your target machine is 14353d137310SThomas Petazzoni unaffected by PCI quirks. 14363d137310SThomas Petazzoni 143741ecc55bSChristoph Lameterconfig SLUB_DEBUG 143841ecc55bSChristoph Lameter default y 14396a108a14SDavid Rientjes bool "Enable SLUB debugging support" if EXPERT 1440f6acb635SChristoph Lameter depends on SLUB && SYSFS 144141ecc55bSChristoph Lameter help 144241ecc55bSChristoph Lameter SLUB has extensive debug support features. Disabling these can 144341ecc55bSChristoph Lameter result in significant savings in code size. This also disables 144441ecc55bSChristoph Lameter SLUB sysfs support. /sys/slab will not exist and there will be 144541ecc55bSChristoph Lameter no support for cache validation etc. 144641ecc55bSChristoph Lameter 1447b943c460SRandy Dunlapconfig COMPAT_BRK 1448b943c460SRandy Dunlap bool "Disable heap randomization" 1449b943c460SRandy Dunlap default y 1450b943c460SRandy Dunlap help 1451b943c460SRandy Dunlap Randomizing heap placement makes heap exploits harder, but it 1452b943c460SRandy Dunlap also breaks ancient binaries (including anything libc5 based). 1453b943c460SRandy Dunlap This option changes the bootup default to heap randomization 1454692105b8SMatt LaPlante disabled, and can be overridden at runtime by setting 1455b943c460SRandy Dunlap /proc/sys/kernel/randomize_va_space to 2. 1456b943c460SRandy Dunlap 1457b943c460SRandy Dunlap On non-ancient distros (post-2000 ones) N is usually a safe choice. 1458b943c460SRandy Dunlap 145981819f0fSChristoph Lameterchoice 146081819f0fSChristoph Lameter prompt "Choose SLAB allocator" 1461a0acd820SChristoph Lameter default SLUB 146281819f0fSChristoph Lameter help 146381819f0fSChristoph Lameter This option allows to select a slab allocator. 146481819f0fSChristoph Lameter 146581819f0fSChristoph Lameterconfig SLAB 146681819f0fSChristoph Lameter bool "SLAB" 146781819f0fSChristoph Lameter help 146881819f0fSChristoph Lameter The regular slab allocator that is established and known to work 146934013886SChristoph Lameter well in all environments. It organizes cache hot objects in 147002f56210SSimon Arlott per cpu and per node queues. 147181819f0fSChristoph Lameter 147281819f0fSChristoph Lameterconfig SLUB 147381819f0fSChristoph Lameter bool "SLUB (Unqueued Allocator)" 147481819f0fSChristoph Lameter help 147581819f0fSChristoph Lameter SLUB is a slab allocator that minimizes cache line usage 147681819f0fSChristoph Lameter instead of managing queues of cached objects (SLAB approach). 147781819f0fSChristoph Lameter Per cpu caching is realized using slabs of objects instead 147881819f0fSChristoph Lameter of queues of objects. SLUB can use memory efficiently 147902f56210SSimon Arlott and has enhanced diagnostics. SLUB is the default choice for 148002f56210SSimon Arlott a slab allocator. 148181819f0fSChristoph Lameter 148281819f0fSChristoph Lameterconfig SLOB 14836a108a14SDavid Rientjes depends on EXPERT 148481819f0fSChristoph Lameter bool "SLOB (Simple Allocator)" 148581819f0fSChristoph Lameter help 148637291458SMatt Mackall SLOB replaces the stock allocator with a drastically simpler 148737291458SMatt Mackall allocator. SLOB is generally more space efficient but 148837291458SMatt Mackall does not perform as well on large systems. 148981819f0fSChristoph Lameter 149081819f0fSChristoph Lameterendchoice 149181819f0fSChristoph Lameter 1492ea637639SJie Zhangconfig MMAP_ALLOW_UNINITIALIZED 1493ea637639SJie Zhang bool "Allow mmapped anonymous memory to be uninitialized" 14946a108a14SDavid Rientjes depends on EXPERT && !MMU 1495ea637639SJie Zhang default n 1496ea637639SJie Zhang help 1497ea637639SJie Zhang Normally, and according to the Linux spec, anonymous memory obtained 1498ea637639SJie Zhang from mmap() has it's contents cleared before it is passed to 1499ea637639SJie Zhang userspace. Enabling this config option allows you to request that 1500ea637639SJie Zhang mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus 1501ea637639SJie Zhang providing a huge performance boost. If this option is not enabled, 1502ea637639SJie Zhang then the flag will be ignored. 1503ea637639SJie Zhang 1504ea637639SJie Zhang This is taken advantage of by uClibc's malloc(), and also by 1505ea637639SJie Zhang ELF-FDPIC binfmt's brk and stack allocator. 1506ea637639SJie Zhang 1507ea637639SJie Zhang Because of the obvious security issues, this option should only be 1508ea637639SJie Zhang enabled on embedded devices where you control what is run in 1509ea637639SJie Zhang userspace. Since that isn't generally a problem on no-MMU systems, 1510ea637639SJie Zhang it is normally safe to say Y here. 1511ea637639SJie Zhang 1512ea637639SJie Zhang See Documentation/nommu-mmap.txt for more information. 1513ea637639SJie Zhang 1514125e5645SMathieu Desnoyersconfig PROFILING 1515b309a294SRobert Richter bool "Profiling support" 1516125e5645SMathieu Desnoyers help 1517125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 1518125e5645SMathieu Desnoyers by profilers such as OProfile. 1519125e5645SMathieu Desnoyers 15205f87f112SIngo Molnar# 15215f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 15225f87f112SIngo Molnar# dynamically changed for a probe function. 15235f87f112SIngo Molnar# 152497e1c18eSMathieu Desnoyersconfig TRACEPOINTS 15255f87f112SIngo Molnar bool 152697e1c18eSMathieu Desnoyers 1527fb32e03fSMathieu Desnoyerssource "arch/Kconfig" 1528fb32e03fSMathieu Desnoyers 15291da177e4SLinus Torvaldsendmenu # General setup 15301da177e4SLinus Torvalds 1531ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT 1532ee7e5516SDmitry Baryshkov bool 1533ee7e5516SDmitry Baryshkov default n 1534ee7e5516SDmitry Baryshkov 1535158a9624SLinus Torvaldsconfig SLABINFO 1536158a9624SLinus Torvalds bool 1537158a9624SLinus Torvalds depends on PROC_FS 15380f389ec6SChristoph Lameter depends on SLAB || SLUB_DEBUG 1539158a9624SLinus Torvalds default y 1540158a9624SLinus Torvalds 1541ae81f9e3SChuck Ebbertconfig RT_MUTEXES 1542ae81f9e3SChuck Ebbert boolean 1543ae81f9e3SChuck Ebbert 15441da177e4SLinus Torvaldsconfig BASE_SMALL 15451da177e4SLinus Torvalds int 15461da177e4SLinus Torvalds default 0 if BASE_FULL 15471da177e4SLinus Torvalds default 1 if !BASE_FULL 15481da177e4SLinus Torvalds 154966da5733SJan Engelhardtmenuconfig MODULES 15501da177e4SLinus Torvalds bool "Enable loadable module support" 15511da177e4SLinus Torvalds help 15521da177e4SLinus Torvalds Kernel modules are small pieces of compiled code which can 15531da177e4SLinus Torvalds be inserted in the running kernel, rather than being 15541da177e4SLinus Torvalds permanently built into the kernel. You use the "modprobe" 15551da177e4SLinus Torvalds tool to add (and sometimes remove) them. If you say Y here, 15561da177e4SLinus Torvalds many parts of the kernel can be built as modules (by 15571da177e4SLinus Torvalds answering M instead of Y where indicated): this is most 15581da177e4SLinus Torvalds useful for infrequently used options which are not required 15591da177e4SLinus Torvalds for booting. For more information, see the man pages for 15601da177e4SLinus Torvalds modprobe, lsmod, modinfo, insmod and rmmod. 15611da177e4SLinus Torvalds 15621da177e4SLinus Torvalds If you say Y here, you will need to run "make 15631da177e4SLinus Torvalds modules_install" to put the modules under /lib/modules/ 15641da177e4SLinus Torvalds where modprobe can find them (you may need to be root to do 15651da177e4SLinus Torvalds this). 15661da177e4SLinus Torvalds 15671da177e4SLinus Torvalds If unsure, say Y. 15681da177e4SLinus Torvalds 15690b0de144SRobert P. J. Dayif MODULES 15700b0de144SRobert P. J. Day 1571826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD 1572826e4506SLinus Torvalds bool "Forced module loading" 1573826e4506SLinus Torvalds default n 1574826e4506SLinus Torvalds help 157591e37a79SRusty Russell Allow loading of modules without version information (ie. modprobe 157691e37a79SRusty Russell --force). Forced module loading sets the 'F' (forced) taint flag and 157791e37a79SRusty Russell is usually a really bad idea. 1578826e4506SLinus Torvalds 15791da177e4SLinus Torvaldsconfig MODULE_UNLOAD 15801da177e4SLinus Torvalds bool "Module unloading" 15811da177e4SLinus Torvalds help 15821da177e4SLinus Torvalds Without this option you will not be able to unload any 15831da177e4SLinus Torvalds modules (note that some modules may not be unloadable 1584f7f5b675SDenys Vlasenko anyway), which makes your kernel smaller, faster 1585f7f5b675SDenys Vlasenko and simpler. If unsure, say Y. 15861da177e4SLinus Torvalds 15871da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD 15881da177e4SLinus Torvalds bool "Forced module unloading" 15891da177e4SLinus Torvalds depends on MODULE_UNLOAD && EXPERIMENTAL 15901da177e4SLinus Torvalds help 15911da177e4SLinus Torvalds This option allows you to force a module to unload, even if the 15921da177e4SLinus Torvalds kernel believes it is unsafe: the kernel will remove the module 15931da177e4SLinus Torvalds without waiting for anyone to stop using it (using the -f option to 15941da177e4SLinus Torvalds rmmod). This is mainly for kernel developers and desperate users. 15951da177e4SLinus Torvalds If unsure, say N. 15961da177e4SLinus Torvalds 15971da177e4SLinus Torvaldsconfig MODVERSIONS 15980d541643SSam Ravnborg bool "Module versioning support" 15991da177e4SLinus Torvalds help 16001da177e4SLinus Torvalds Usually, you have to use modules compiled with your kernel. 16011da177e4SLinus Torvalds Saying Y here makes it sometimes possible to use modules 16021da177e4SLinus Torvalds compiled for different kernels, by adding enough information 16031da177e4SLinus Torvalds to the modules to (hopefully) spot any changes which would 16041da177e4SLinus Torvalds make them incompatible with the kernel you are running. If 16051da177e4SLinus Torvalds unsure, say N. 16061da177e4SLinus Torvalds 16071da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL 16081da177e4SLinus Torvalds bool "Source checksum for all modules" 16091da177e4SLinus Torvalds help 16101da177e4SLinus Torvalds Modules which contain a MODULE_VERSION get an extra "srcversion" 16111da177e4SLinus Torvalds field inserted into their modinfo section, which contains a 16121da177e4SLinus Torvalds sum of the source files which made it. This helps maintainers 16131da177e4SLinus Torvalds see exactly which source was used to build a module (since 16141da177e4SLinus Torvalds others sometimes change the module source without updating 16151da177e4SLinus Torvalds the version). With this option, such a "srcversion" field 16161da177e4SLinus Torvalds will be created for all modules. If unsure, say N. 16171da177e4SLinus Torvalds 16180b0de144SRobert P. J. Dayendif # MODULES 16190b0de144SRobert P. J. Day 162098a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 162198a79d6aSRusty Russell bool 162298a79d6aSRusty Russell help 16235f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 16245f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 162598a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 162698a79d6aSRusty Russell it was better to provide this option than to break all the archs 1627692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 162898a79d6aSRusty Russell 16291da177e4SLinus Torvaldsconfig STOP_MACHINE 16301da177e4SLinus Torvalds bool 16311da177e4SLinus Torvalds default y 16321da177e4SLinus Torvalds depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 16331da177e4SLinus Torvalds help 16341da177e4SLinus Torvalds Need stop_machine() primitive. 16353a65dfe8SJens Axboe 16363a65dfe8SJens Axboesource "block/Kconfig" 1637e98c3202SAvi Kivity 1638e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 1639e98c3202SAvi Kivity bool 1640e260be67SPaul E. McKenney 164116295becSSteffen Klassertconfig PADATA 164216295becSSteffen Klassert depends on SMP 164316295becSSteffen Klassert bool 164416295becSSteffen Klassert 16456beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 1646