1ec8f24b7SThomas Gleixner# SPDX-License-Identifier: GPL-2.0-only 28b59cd81SMasahiro Yamadaconfig CC_VERSION_TEXT 38b59cd81SMasahiro Yamada string 48b59cd81SMasahiro Yamada default "$(CC_VERSION_TEXT)" 58b59cd81SMasahiro Yamada help 68b59cd81SMasahiro Yamada This is used in unclear ways: 78b59cd81SMasahiro Yamada 88b59cd81SMasahiro Yamada - Re-run Kconfig when the compiler is updated 98b59cd81SMasahiro Yamada The 'default' property references the environment variable, 108b59cd81SMasahiro Yamada CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd. 118b59cd81SMasahiro Yamada When the compiler is updated, Kconfig will be invoked. 128b59cd81SMasahiro Yamada 13f9c8bc46SBhaskar Chowdhury - Ensure full rebuild when the compiler is updated 14ce6ed1c4SMasahiro Yamada include/linux/compiler-version.h contains this option in the comment 150e0345b7SAlexey Dobriyan line so fixdep adds include/config/CC_VERSION_TEXT into the 16ce6ed1c4SMasahiro Yamada auto-generated dependency. When the compiler is updated, syncconfig 17ce6ed1c4SMasahiro Yamada will touch it and then every file will be rebuilt. 188b59cd81SMasahiro Yamada 19a4353898SMasahiro Yamadaconfig CC_IS_GCC 20aec6c60aSMasahiro Yamada def_bool $(success,test "$(cc-name)" = GCC) 21a4353898SMasahiro Yamada 22a4353898SMasahiro Yamadaconfig GCC_VERSION 23a4353898SMasahiro Yamada int 24aec6c60aSMasahiro Yamada default $(cc-version) if CC_IS_GCC 25a4353898SMasahiro Yamada default 0 26a4353898SMasahiro Yamada 27469cb737SMasahiro Yamadaconfig CC_IS_CLANG 28aec6c60aSMasahiro Yamada def_bool $(success,test "$(cc-name)" = Clang) 29b744b43fSSami Tolvanen 30469cb737SMasahiro Yamadaconfig CLANG_VERSION 31469cb737SMasahiro Yamada int 32aec6c60aSMasahiro Yamada default $(cc-version) if CC_IS_CLANG 33aec6c60aSMasahiro Yamada default 0 34469cb737SMasahiro Yamada 35ba64beb1SMasahiro Yamadaconfig AS_IS_GNU 36ba64beb1SMasahiro Yamada def_bool $(success,test "$(as-name)" = GNU) 37ba64beb1SMasahiro Yamada 38ba64beb1SMasahiro Yamadaconfig AS_IS_LLVM 39ba64beb1SMasahiro Yamada def_bool $(success,test "$(as-name)" = LLVM) 40ba64beb1SMasahiro Yamada 41ba64beb1SMasahiro Yamadaconfig AS_VERSION 42ba64beb1SMasahiro Yamada int 43ba64beb1SMasahiro Yamada # Use clang version if this is the integrated assembler 44ba64beb1SMasahiro Yamada default CLANG_VERSION if AS_IS_LLVM 45ba64beb1SMasahiro Yamada default $(as-version) 46ba64beb1SMasahiro Yamada 4702aff859SMasahiro Yamadaconfig LD_IS_BFD 4802aff859SMasahiro Yamada def_bool $(success,test "$(ld-name)" = BFD) 4902aff859SMasahiro Yamada 5002aff859SMasahiro Yamadaconfig LD_VERSION 5102aff859SMasahiro Yamada int 5202aff859SMasahiro Yamada default $(ld-version) if LD_IS_BFD 5302aff859SMasahiro Yamada default 0 5402aff859SMasahiro Yamada 5502aff859SMasahiro Yamadaconfig LD_IS_LLD 5602aff859SMasahiro Yamada def_bool $(success,test "$(ld-name)" = LLD) 57c65eacbeSAndy Lutomirski 58d5750cd3SNathan Chancellorconfig LLD_VERSION 59d5750cd3SNathan Chancellor int 6002aff859SMasahiro Yamada default $(ld-version) if LD_IS_LLD 6102aff859SMasahiro Yamada default 0 62d5750cd3SNathan Chancellor 636e74c6b5SMiguel Ojedaconfig RUSTC_VERSION 646e74c6b5SMiguel Ojeda int 65af0121c2SGary Guo default $(rustc-version) 666e74c6b5SMiguel Ojeda help 676e74c6b5SMiguel Ojeda It does not depend on `RUST` since that one may need to use the version 686e74c6b5SMiguel Ojeda in a `depends on`. 696e74c6b5SMiguel Ojeda 702f7ab126SMiguel Ojedaconfig RUST_IS_AVAILABLE 712f7ab126SMiguel Ojeda def_bool $(success,$(srctree)/scripts/rust_is_available.sh) 722f7ab126SMiguel Ojeda help 732f7ab126SMiguel Ojeda This shows whether a suitable Rust toolchain is available (found). 742f7ab126SMiguel Ojeda 752f7ab126SMiguel Ojeda Please see Documentation/rust/quick-start.rst for instructions on how 76eacf96d2SColin Ian King to satisfy the build requirements of Rust support. 772f7ab126SMiguel Ojeda 782f7ab126SMiguel Ojeda In particular, the Makefile target 'rustavailable' is useful to check 792f7ab126SMiguel Ojeda why the Rust toolchain is not being detected. 802f7ab126SMiguel Ojeda 81af0121c2SGary Guoconfig RUSTC_LLVM_VERSION 82af0121c2SGary Guo int 83af0121c2SGary Guo default $(rustc-llvm-version) 84af0121c2SGary Guo 85deab487eSThomas Weißschuhconfig ARCH_HAS_CC_CAN_LINK 86deab487eSThomas Weißschuh bool 87deab487eSThomas Weißschuh 881a927fd3SMasahiro Yamadaconfig CC_CAN_LINK 899371f86eSMasahiro Yamada bool 90deab487eSThomas Weißschuh default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK 9180623f2cSThomas Weißschuh default $(cc_can_link_user,$(m64-flag)) if 64BIT 9280623f2cSThomas Weißschuh default $(cc_can_link_user,$(m32-flag)) 931a927fd3SMasahiro Yamada 94f2f6a8e8SMark Rutland# Fixed in GCC 14, 13.3, 12.4 and 11.5 95f2f6a8e8SMark Rutland# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 96f2f6a8e8SMark Rutlandconfig GCC_ASM_GOTO_OUTPUT_BROKEN 97f2f6a8e8SMark Rutland bool 98f2f6a8e8SMark Rutland depends on CC_IS_GCC 99f2f6a8e8SMark Rutland default y if GCC_VERSION < 110500 100f2f6a8e8SMark Rutland default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 101f2f6a8e8SMark Rutland default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 102f2f6a8e8SMark Rutland 103587f1701SNick Desaulniersconfig CC_HAS_ASM_GOTO_OUTPUT 104f2f6a8e8SMark Rutland def_bool y 105f2f6a8e8SMark Rutland depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 106e2ffa15bSThomas Gleixner # Detect basic support 107f2f6a8e8SMark Rutland depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) 108e2ffa15bSThomas Gleixner # Detect clang (< v17) scoped label issues 109fde0ab43SLinus Torvalds depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) 110587f1701SNick Desaulniers 1111aa0e8b1SSean Christophersonconfig CC_HAS_ASM_GOTO_TIED_OUTPUT 1121aa0e8b1SSean Christopherson depends on CC_HAS_ASM_GOTO_OUTPUT 1131aa0e8b1SSean Christopherson # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 114534bd703SAlexandre Belloni def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null) 1151aa0e8b1SSean Christopherson 1165cf896fbSPeter Collingbourneconfig TOOLS_SUPPORT_RELR 1172d122942SWill Deacon def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 1185cf896fbSPeter Collingbourne 119eb111869SRasmus Villemoesconfig CC_HAS_ASM_INLINE 120eb111869SRasmus Villemoes def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 121eb111869SRasmus Villemoes 122f72e2cffSHeiko Carstensconfig CC_HAS_ASSUME 123f72e2cffSHeiko Carstens bool 124f72e2cffSHeiko Carstens # clang needs to be at least 19.1.0 since the meaning of the assume 125f72e2cffSHeiko Carstens # attribute changed: 126f72e2cffSHeiko Carstens # https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17 127f72e2cffSHeiko Carstens default y if CC_IS_CLANG && CLANG_VERSION >= 190100 128f72e2cffSHeiko Carstens # supported since gcc 13.1.0 129f72e2cffSHeiko Carstens # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654 130f72e2cffSHeiko Carstens default y if CC_IS_GCC && GCC_VERSION >= 130100 131f72e2cffSHeiko Carstens 13251c2ee6dSNick Desaulniersconfig CC_HAS_NO_PROFILE_FN_ATTR 13351c2ee6dSNick Desaulniers def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 13451c2ee6dSNick Desaulniers 135f06e108aSJan Hendrik Farrconfig CC_HAS_COUNTED_BY 1365106c650SJan Hendrik Farr bool 13786a9b125SNathan Chancellor # clang needs to be at least 20.1.0 to avoid potential crashes 13886a9b125SNathan Chancellor # when building structures that contain __counted_by 13986a9b125SNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/2114 14086a9b125SNathan Chancellor # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 14186a9b125SNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION >= 200100 1425106c650SJan Hendrik Farr # supported since gcc 15.1.0 1435106c650SJan Hendrik Farr # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 1445106c650SJan Hendrik Farr default y if CC_IS_GCC && GCC_VERSION >= 150100 145f06e108aSJan Hendrik Farr 146b688f369SKees Cookconfig CC_HAS_MULTIDIMENSIONAL_NONSTRING 147b688f369SKees Cook def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 148b688f369SKees Cook 149e7607f7dSNathan Chancellorconfig LD_CAN_USE_KEEP_IN_OVERLAY 150e7607f7dSNathan Chancellor # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 151e7607f7dSNathan Chancellor # https://github.com/llvm/llvm-project/pull/130661 152e7607f7dSNathan Chancellor def_bool LD_IS_BFD || LLD_VERSION >= 210000 153e7607f7dSNathan Chancellor 15488622323SAlexandre Courbotconfig RUSTC_HAS_SLICE_AS_FLATTENED 15588622323SAlexandre Courbot def_bool RUSTC_VERSION >= 108000 15688622323SAlexandre Courbot 15747cb6bf7SXiangfei Dingconfig RUSTC_HAS_COERCE_POINTEE 15847cb6bf7SXiangfei Ding def_bool RUSTC_VERSION >= 108400 15947cb6bf7SXiangfei Ding 16036174d16SMiguel Ojedaconfig RUSTC_HAS_SPAN_FILE 16136174d16SMiguel Ojeda def_bool RUSTC_VERSION >= 108800 16236174d16SMiguel Ojeda 1637129ea6eSMiguel Ojedaconfig RUSTC_HAS_UNNECESSARY_TRANSMUTES 1647129ea6eSMiguel Ojeda def_bool RUSTC_VERSION >= 108800 1657129ea6eSMiguel Ojeda 1660aa2b78cSBoqun Fengconfig RUSTC_HAS_FILE_WITH_NUL 1670aa2b78cSBoqun Feng def_bool RUSTC_VERSION >= 108900 1680aa2b78cSBoqun Feng 169c09461a0SAlice Ryhlconfig RUSTC_HAS_FILE_AS_C_STR 170c09461a0SAlice Ryhl def_bool RUSTC_VERSION >= 109100 171c09461a0SAlice Ryhl 172613fe169SNathan Chancellorconfig PAHOLE_VERSION 173613fe169SNathan Chancellor int 174613fe169SNathan Chancellor default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 175613fe169SNathan Chancellor 176b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 177b99b87f7SPeter Oberparleiter bool 178b99b87f7SPeter Oberparleiter 179e360adbeSPeter Zijlstraconfig IRQ_WORK 180fd0a68a2STejun Heo def_bool y if SMP 181e360adbeSPeter Zijlstra 18210916706SShile Zhangconfig BUILDTIME_TABLE_SORT 1831dbdc6f1SDavid Daney bool 1841dbdc6f1SDavid Daney 185c65eacbeSAndy Lutomirskiconfig THREAD_INFO_IN_TASK 186c65eacbeSAndy Lutomirski bool 187c65eacbeSAndy Lutomirski help 188c65eacbeSAndy Lutomirski Select this to move thread_info off the stack into task_struct. To 189c65eacbeSAndy Lutomirski make this work, an arch will need to remove all thread_info fields 190c65eacbeSAndy Lutomirski except flags and fix any runtime bugs. 191c65eacbeSAndy Lutomirski 192c6c314a6SAndy Lutomirski One subtle change that will be needed is to use try_get_task_stack() 193c6c314a6SAndy Lutomirski and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 194c6c314a6SAndy Lutomirski 195ff0cfc66SAl Boldimenu "General setup" 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvaldsconfig BROKEN 1981da177e4SLinus Torvalds bool 199fefbeed8SAndrew Morton help 200fefbeed8SAndrew Morton This option allows you to choose whether you want to try to 201fefbeed8SAndrew Morton compile (and fix) old drivers that haven't been updated to 202fefbeed8SAndrew Morton new infrastructure. 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 2051da177e4SLinus Torvalds bool 2061da177e4SLinus Torvalds depends on BROKEN || !SMP 2071da177e4SLinus Torvalds default y 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 2101da177e4SLinus Torvalds int 211dd673bcaSAdrian Bunk default 32 if !UML 212dd673bcaSAdrian Bunk default 128 if UML 2131da177e4SLinus Torvalds help 21434ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 21534ad92c2SRandy Dunlap variables passed to init from the kernel command line. 2161da177e4SLinus Torvalds 2174bb16672SJiri Slabyconfig COMPILE_TEST 2184bb16672SJiri Slaby bool "Compile also drivers which will not load" 219ea29b20aSMasahiro Yamada depends on HAS_IOMEM 2204bb16672SJiri Slaby help 2214bb16672SJiri Slaby Some drivers can be compiled on a different platform than they are 2224bb16672SJiri Slaby intended to be run on. Despite they cannot be loaded there (or even 2234bb16672SJiri Slaby when they load they cannot be used due to missing HW support), 2244bb16672SJiri Slaby developers still, opposing to distributors, might want to build such 2254bb16672SJiri Slaby drivers to compile-test them. 2264bb16672SJiri Slaby 2274bb16672SJiri Slaby If you are a developer and want to build everything available, say Y 2284bb16672SJiri Slaby here. If you are a user/distributor, say N here to exclude useless 2294bb16672SJiri Slaby drivers to be distributed. 2304bb16672SJiri Slaby 2313fe617ccSLinus Torvaldsconfig WERROR 2323fe617ccSLinus Torvalds bool "Compile the kernel with warnings as errors" 233b339ec9cSMarco Elver default COMPILE_TEST 2343fe617ccSLinus Torvalds help 2353fe617ccSLinus Torvalds A kernel build should not cause any compiler warnings, and this 2362f7ab126SMiguel Ojeda enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 237e1789d7cSXin Li to enforce that rule by default. Certain warnings from other tools 238e1789d7cSXin Li such as the linker may be upgraded to errors with this option as 239e1789d7cSXin Li well. 2403fe617ccSLinus Torvalds 241e1789d7cSXin Li However, if you have a new (or very old) compiler or linker with odd 242e1789d7cSXin Li and unusual warnings, or you have some architecture with problems, 2433fe617ccSLinus Torvalds you may need to disable this config option in order to 2443fe617ccSLinus Torvalds successfully build the kernel. 2453fe617ccSLinus Torvalds 2463fe617ccSLinus Torvalds If in doubt, say Y. 2473fe617ccSLinus Torvalds 248d6fc9fcbSMasahiro Yamadaconfig UAPI_HEADER_TEST 249d6fc9fcbSMasahiro Yamada bool "Compile test UAPI headers" 250fcbb8461SMasahiro Yamada depends on HEADERS_INSTALL && CC_CAN_LINK 251d6fc9fcbSMasahiro Yamada help 252d6fc9fcbSMasahiro Yamada Compile test headers exported to user-space to ensure they are 253d6fc9fcbSMasahiro Yamada self-contained, i.e. compilable as standalone units. 254d6fc9fcbSMasahiro Yamada 255d6fc9fcbSMasahiro Yamada If you are a developer or tester and want to ensure the exported 256d6fc9fcbSMasahiro Yamada headers are self-contained, say Y here. Otherwise, choose N. 257d6fc9fcbSMasahiro Yamada 2581da177e4SLinus Torvaldsconfig LOCALVERSION 2591da177e4SLinus Torvalds string "Local version - append to kernel release" 2601da177e4SLinus Torvalds help 2611da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 2621da177e4SLinus Torvalds This will show up when you type uname, for example. 2631da177e4SLinus Torvalds The string you set here will be appended after the contents of 2641da177e4SLinus Torvalds any files with a filename matching localversion* in your 2651da177e4SLinus Torvalds object and source tree, in that order. Your total string can 2661da177e4SLinus Torvalds be a maximum of 64 characters. 2671da177e4SLinus Torvalds 268aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 269aaebf433SRyan Anderson bool "Automatically append version information to the version string" 270aaebf433SRyan Anderson default y 271ac3339baSAlexey Dobriyan depends on !COMPILE_TEST 272aaebf433SRyan Anderson help 273aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 2746e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 2756e5a5420SRobert P. J. Day top of tree revision. 276aaebf433SRyan Anderson 277aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 2786e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 279aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 2806e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 281aaebf433SRyan Anderson 2820f9c608dSRasmus Villemoes (The actual string used here is the first 12 characters produced 2836e5a5420SRobert P. J. Day by running the command: 2846e5a5420SRobert P. J. Day 2856e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 2866e5a5420SRobert P. J. Day 2876e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 288aaebf433SRyan Anderson 2899afb719eSLaura Abbottconfig BUILD_SALT 2909afb719eSLaura Abbott string "Build ID Salt" 2919afb719eSLaura Abbott default "" 2929afb719eSLaura Abbott help 2939afb719eSLaura Abbott The build ID is used to link binaries and their debug info. Setting 2949afb719eSLaura Abbott this option will use the value in the calculation of the build id. 2959afb719eSLaura Abbott This is mostly useful for distributions which want to ensure the 2969afb719eSLaura Abbott build is unique between builds. It's safe to leave the default. 2979afb719eSLaura Abbott 2982e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 2992e9f3bddSH. Peter Anvin bool 3002e9f3bddSH. Peter Anvin 3012e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 3022e9f3bddSH. Peter Anvin bool 3032e9f3bddSH. Peter Anvin 3042e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 3052e9f3bddSH. Peter Anvin bool 3062e9f3bddSH. Peter Anvin 3073ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 3083ebe1243SLasse Collin bool 3093ebe1243SLasse Collin 3107dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 3117dd65febSAlbin Tonnerre bool 3127dd65febSAlbin Tonnerre 313e76e1fdfSKyungsik Leeconfig HAVE_KERNEL_LZ4 314e76e1fdfSKyungsik Lee bool 315e76e1fdfSKyungsik Lee 31648f7ddf7SNick Terrellconfig HAVE_KERNEL_ZSTD 31748f7ddf7SNick Terrell bool 31848f7ddf7SNick Terrell 319f16466afSVasily Gorbikconfig HAVE_KERNEL_UNCOMPRESSED 320f16466afSVasily Gorbik bool 321f16466afSVasily Gorbik 32230d65dbfSAlain Knaffchoice 32330d65dbfSAlain Knaff prompt "Kernel compression mode" 32430d65dbfSAlain Knaff default KERNEL_GZIP 32548f7ddf7SNick Terrell depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED 32630d65dbfSAlain Knaff help 32730d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 32830d65dbfSAlain Knaff Several compression algorithms are available, which differ 32930d65dbfSAlain Knaff in efficiency, compression and decompression speed. 33030d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 33130d65dbfSAlain Knaff Decompression speed is relevant at each boot. 33230d65dbfSAlain Knaff 33330d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 33430d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 33530d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 33630d65dbfSAlain Knaff supplied by Christian Ludwig) 33730d65dbfSAlain Knaff 33830d65dbfSAlain Knaff High compression options are mostly useful for users, who 33930d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 34030d65dbfSAlain Knaff size matters less. 34130d65dbfSAlain Knaff 34230d65dbfSAlain Knaff If in doubt, select 'gzip' 34330d65dbfSAlain Knaff 34430d65dbfSAlain Knaffconfig KERNEL_GZIP 34530d65dbfSAlain Knaff bool "Gzip" 3462e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 34730d65dbfSAlain Knaff help 3487dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 3497dd65febSAlbin Tonnerre between compression ratio and decompression speed. 35030d65dbfSAlain Knaff 35130d65dbfSAlain Knaffconfig KERNEL_BZIP2 35230d65dbfSAlain Knaff bool "Bzip2" 3532e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 35430d65dbfSAlain Knaff help 35530d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 3560a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 3572e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 3582e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 3592e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 36030d65dbfSAlain Knaff 36130d65dbfSAlain Knaffconfig KERNEL_LZMA 36230d65dbfSAlain Knaff bool "LZMA" 3632e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 36430d65dbfSAlain Knaff help 3650a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 3660a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 3670a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 36830d65dbfSAlain Knaff 3693ebe1243SLasse Collinconfig KERNEL_XZ 3703ebe1243SLasse Collin bool "XZ" 3713ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 3723ebe1243SLasse Collin help 3733ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 3743ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 3753ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 3763ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 3777472ff8aSLasse Collin filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 3787472ff8aSLasse Collin and SPARC), XZ will create a few percent smaller kernel than 3797472ff8aSLasse Collin plain LZMA. 3803ebe1243SLasse Collin 3813ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 3823ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 3833ebe1243SLasse Collin and LZO. Compression is slow. 3843ebe1243SLasse Collin 3857dd65febSAlbin Tonnerreconfig KERNEL_LZO 3867dd65febSAlbin Tonnerre bool "LZO" 3877dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 3887dd65febSAlbin Tonnerre help 3890a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 390681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 3917dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 3927dd65febSAlbin Tonnerre 393e76e1fdfSKyungsik Leeconfig KERNEL_LZ4 394e76e1fdfSKyungsik Lee bool "LZ4" 395e76e1fdfSKyungsik Lee depends on HAVE_KERNEL_LZ4 396e76e1fdfSKyungsik Lee help 397e76e1fdfSKyungsik Lee LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 398e76e1fdfSKyungsik Lee A preliminary version of LZ4 de/compression tool is available at 399e76e1fdfSKyungsik Lee <https://code.google.com/p/lz4/>. 400e76e1fdfSKyungsik Lee 401e76e1fdfSKyungsik Lee Its compression ratio is worse than LZO. The size of the kernel 402e76e1fdfSKyungsik Lee is about 8% bigger than LZO. But the decompression speed is 403e76e1fdfSKyungsik Lee faster than LZO. 404e76e1fdfSKyungsik Lee 40548f7ddf7SNick Terrellconfig KERNEL_ZSTD 40648f7ddf7SNick Terrell bool "ZSTD" 40748f7ddf7SNick Terrell depends on HAVE_KERNEL_ZSTD 40848f7ddf7SNick Terrell help 40948f7ddf7SNick Terrell ZSTD is a compression algorithm targeting intermediate compression 41048f7ddf7SNick Terrell with fast decompression speed. It will compress better than GZIP and 41148f7ddf7SNick Terrell decompress around the same speed as LZO, but slower than LZ4. You 41248f7ddf7SNick Terrell will need at least 192 KB RAM or more for booting. The zstd command 41348f7ddf7SNick Terrell line tool is required for compression. 41448f7ddf7SNick Terrell 415f16466afSVasily Gorbikconfig KERNEL_UNCOMPRESSED 416f16466afSVasily Gorbik bool "None" 417f16466afSVasily Gorbik depends on HAVE_KERNEL_UNCOMPRESSED 418f16466afSVasily Gorbik help 419f16466afSVasily Gorbik Produce uncompressed kernel image. This option is usually not what 420f16466afSVasily Gorbik you want. It is useful for debugging the kernel in slow simulation 421f16466afSVasily Gorbik environments, where decompressing and moving the kernel is awfully 422f16466afSVasily Gorbik slow. This option allows early boot code to skip the decompressor 423f16466afSVasily Gorbik and jump right at uncompressed kernel image. 424f16466afSVasily Gorbik 42530d65dbfSAlain Knaffendchoice 42630d65dbfSAlain Knaff 427ada4ab7aSChris Downconfig DEFAULT_INIT 428ada4ab7aSChris Down string "Default init path" 429ada4ab7aSChris Down default "" 430ada4ab7aSChris Down help 431ada4ab7aSChris Down This option determines the default init for the system if no init= 432ada4ab7aSChris Down option is passed on the kernel command line. If the requested path is 433ada4ab7aSChris Down not present, we will still then move on to attempting further 434ada4ab7aSChris Down locations (e.g. /sbin/init, etc). If this is empty, we will just use 435ada4ab7aSChris Down the fallback list when init= is not passed. 436ada4ab7aSChris Down 437bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 438bd5dc17bSJosh Triplett string "Default hostname" 439bd5dc17bSJosh Triplett default "(none)" 440bd5dc17bSJosh Triplett help 441bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 442bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 443bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 444bd5dc17bSJosh Triplett system more usable with less configuration. 445bd5dc17bSJosh Triplett 4461da177e4SLinus Torvaldsconfig SYSVIPC 4471da177e4SLinus Torvalds bool "System V IPC" 448a7f7f624SMasahiro Yamada help 4491da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 4501da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 4511da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 4521da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 4531da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 4541da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 4551da177e4SLinus Torvalds you'll need to say Y here. 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 4581da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 4591da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 4601da177e4SLinus Torvalds 461a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 462a5494dcdSEric W. Biederman bool 463a5494dcdSEric W. Biederman depends on SYSVIPC 464a5494dcdSEric W. Biederman depends on SYSCTL 465a5494dcdSEric W. Biederman default y 466a5494dcdSEric W. Biederman 4670cbed0eeSGuo Renconfig SYSVIPC_COMPAT 4680cbed0eeSGuo Ren def_bool y 4690cbed0eeSGuo Ren depends on COMPAT && SYSVIPC 4700cbed0eeSGuo Ren 4711da177e4SLinus Torvaldsconfig POSIX_MQUEUE 4721da177e4SLinus Torvalds bool "POSIX Message Queues" 47319c92399SKees Cook depends on NET 474a7f7f624SMasahiro Yamada help 4751da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 4761da177e4SLinus Torvalds queues every message has a priority which decides about succession 4771da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 4781da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 479b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 4801da177e4SLinus Torvalds 4811da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 4821da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 4831da177e4SLinus Torvalds operations on message queues. 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds If unsure, say Y. 4861da177e4SLinus Torvalds 487bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 488bdc8e5f8SSerge E. Hallyn bool 489bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 490bdc8e5f8SSerge E. Hallyn depends on SYSCTL 491bdc8e5f8SSerge E. Hallyn default y 492bdc8e5f8SSerge E. Hallyn 493c73be61cSDavid Howellsconfig WATCH_QUEUE 494c73be61cSDavid Howells bool "General notification queue" 495c73be61cSDavid Howells default n 496c73be61cSDavid Howells help 497c73be61cSDavid Howells 498c73be61cSDavid Howells This is a general notification queue for the kernel to pass events to 499c73be61cSDavid Howells userspace by splicing them into pipes. It can be used in conjunction 500c73be61cSDavid Howells with watches for key/keyring change notifications and device 501c73be61cSDavid Howells notifications. 502c73be61cSDavid Howells 503c02b872aSMauro Carvalho Chehab See Documentation/core-api/watch_queue.rst 504c73be61cSDavid Howells 505226b4ccdSKonstantin Khlebnikovconfig CROSS_MEMORY_ATTACH 506226b4ccdSKonstantin Khlebnikov bool "Enable process_vm_readv/writev syscalls" 507226b4ccdSKonstantin Khlebnikov depends on MMU 508226b4ccdSKonstantin Khlebnikov default y 509226b4ccdSKonstantin Khlebnikov help 510226b4ccdSKonstantin Khlebnikov Enabling this option adds the system calls process_vm_readv and 511226b4ccdSKonstantin Khlebnikov process_vm_writev which allow a process with the correct privileges 512a2a368d9SGeert Uytterhoeven to directly read from or write to another process' address space. 513226b4ccdSKonstantin Khlebnikov See the man page for more details. 514226b4ccdSKonstantin Khlebnikov 5151da177e4SLinus Torvaldsconfig AUDIT 5161da177e4SLinus Torvalds bool "Auditing support" 517804a6a49SChris Wright depends on NET 5181da177e4SLinus Torvalds help 5191da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 5201da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 521cb74ed27SPaul Moore logging of avc messages output). System call auditing is included 522cb74ed27SPaul Moore on architectures which support it. 5231da177e4SLinus Torvalds 5247a017721SAKASHI Takahiroconfig HAVE_ARCH_AUDITSYSCALL 5257a017721SAKASHI Takahiro bool 5267a017721SAKASHI Takahiro 5271da177e4SLinus Torvaldsconfig AUDITSYSCALL 528cb74ed27SPaul Moore def_bool y 5297a017721SAKASHI Takahiro depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 53028a3a7ebSEric Paris select FSNOTIFY 53174c3cbe3SAl Viro 532d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 533764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 534b24abcffSDaniel Borkmannsource "kernel/bpf/Kconfig" 53587a4c375SChristoph Hellwigsource "kernel/Kconfig.preempt" 536d9817ebeSThomas Gleixner 537391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 538391dc69cSFrederic Weisbecker 539abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 540abf917cdSFrederic Weisbecker bool 541abf917cdSFrederic Weisbecker 542fdf9c356SFrederic Weisbeckerchoice 543fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 54402382affSNicholas Piggin default TICK_CPU_ACCOUNTING 545fdf9c356SFrederic Weisbecker 546fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 547fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 548fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 549c58b0df1SFrederic Weisbecker depends on !S390 && !NO_HZ_FULL 550fdf9c356SFrederic Weisbecker help 551fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 552fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 553fdf9c356SFrederic Weisbecker granularity. 554fdf9c356SFrederic Weisbecker 555fdf9c356SFrederic Weisbecker If unsure, say Y. 556fdf9c356SFrederic Weisbecker 557abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE 558391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 559c58b0df1SFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 560abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 561391dc69cSFrederic Weisbecker help 562391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 563391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 564391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 565391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 566391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 567391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 568391dc69cSFrederic Weisbecker systems. 569391dc69cSFrederic Weisbecker 570abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN 571abf917cdSFrederic Weisbecker bool "Full dynticks CPU time accounting" 57224a9c541SFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING_USER 573554b0004SKevin Hilman depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 574041a1574SArnd Bergmann depends on GENERIC_CLOCKEVENTS 575abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 57624a9c541SFrederic Weisbecker select CONTEXT_TRACKING_USER 577abf917cdSFrederic Weisbecker help 578abf917cdSFrederic Weisbecker Select this option to enable task and CPU time accounting on full 579abf917cdSFrederic Weisbecker dynticks systems. This accounting is implemented by watching every 580abf917cdSFrederic Weisbecker kernel-user boundaries using the context tracking subsystem. 581abf917cdSFrederic Weisbecker The accounting is thus performed at the expense of some significant 582abf917cdSFrederic Weisbecker overhead. 583abf917cdSFrederic Weisbecker 584abf917cdSFrederic Weisbecker For now this is only useful if you are working on the full 585abf917cdSFrederic Weisbecker dynticks subsystem development. 586abf917cdSFrederic Weisbecker 587abf917cdSFrederic Weisbecker If unsure, say N. 588abf917cdSFrederic Weisbecker 589b58c3584SRik van Rielendchoice 590b58c3584SRik van Riel 591fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 592fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 593b58c3584SRik van Riel depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 594fdf9c356SFrederic Weisbecker help 595fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 596fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 597fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 598fdf9c356SFrederic Weisbecker small performance impact. 599fdf9c356SFrederic Weisbecker 600fdf9c356SFrederic Weisbecker If in doubt, say N here. 601fdf9c356SFrederic Weisbecker 60211d4afd4SVincent Guittotconfig HAVE_SCHED_AVG_IRQ 60311d4afd4SVincent Guittot def_bool y 60411d4afd4SVincent Guittot depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 60511d4afd4SVincent Guittot depends on SMP 60611d4afd4SVincent Guittot 607d4dbc991SVincent Guittotconfig SCHED_HW_PRESSURE 60898eb401dSValentin Schneider bool 609fcd7c9c3SValentin Schneider default y if ARM && ARM_CPU_TOPOLOGY 610fcd7c9c3SValentin Schneider default y if ARM64 61176504793SThara Gopinath depends on SMP 61298eb401dSValentin Schneider depends on CPU_FREQ_THERMAL 61398eb401dSValentin Schneider help 614d4dbc991SVincent Guittot Select this option to enable HW pressure accounting in the 615d4dbc991SVincent Guittot scheduler. HW pressure is the value conveyed to the scheduler 61698eb401dSValentin Schneider that reflects the reduction in CPU compute capacity resulted from 617d4dbc991SVincent Guittot HW throttling. HW throttling occurs when the performance of 618d4dbc991SVincent Guittot a CPU is capped due to high operating temperatures as an example. 61998eb401dSValentin Schneider 62098eb401dSValentin Schneider If selected, the scheduler will be able to balance tasks accordingly, 62198eb401dSValentin Schneider i.e. put less load on throttled CPUs than on non/less throttled ones. 62298eb401dSValentin Schneider 62398eb401dSValentin Schneider This requires the architecture to implement 624d4dbc991SVincent Guittot arch_update_hw_pressure() and arch_scale_thermal_pressure(). 62576504793SThara Gopinath 626391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 627391dc69cSFrederic Weisbecker bool "BSD Process Accounting" 6282813893fSIulia Manda depends on MULTIUSER 629391dc69cSFrederic Weisbecker help 630391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 631391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 632391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 633391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 634391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 635391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 636391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 637391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 638391dc69cSFrederic Weisbecker information. This is generally a good idea, so say Y. 639391dc69cSFrederic Weisbecker 640391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 641391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 642391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 643391dc69cSFrederic Weisbecker default n 644391dc69cSFrederic Weisbecker help 645391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 646391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 6473903bf94SRandy Dunlap process and its parent. Note that this file format is incompatible 648391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 649391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 650391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 651391dc69cSFrederic Weisbecker 652391dc69cSFrederic Weisbeckerconfig TASKSTATS 65319c92399SKees Cook bool "Export task/process statistics through netlink" 654391dc69cSFrederic Weisbecker depends on NET 6552813893fSIulia Manda depends on MULTIUSER 656391dc69cSFrederic Weisbecker default n 657391dc69cSFrederic Weisbecker help 658391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 659391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 660391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 661391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 662391dc69cSFrederic Weisbecker space on task exit. 663391dc69cSFrederic Weisbecker 664391dc69cSFrederic Weisbecker Say N if unsure. 665391dc69cSFrederic Weisbecker 666391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 66719c92399SKees Cook bool "Enable per-task delay accounting" 668391dc69cSFrederic Weisbecker depends on TASKSTATS 669f6db8347SNaveen N. Rao select SCHED_INFO 670391dc69cSFrederic Weisbecker help 671391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 672391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 673391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 674391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 675391dc69cSFrederic Weisbecker 676391dc69cSFrederic Weisbecker Say N if unsure. 677391dc69cSFrederic Weisbecker 678391dc69cSFrederic Weisbeckerconfig TASK_XACCT 67919c92399SKees Cook bool "Enable extended accounting over taskstats" 680391dc69cSFrederic Weisbecker depends on TASKSTATS 681391dc69cSFrederic Weisbecker help 682391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 683391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 684391dc69cSFrederic Weisbecker 685391dc69cSFrederic Weisbecker Say N if unsure. 686391dc69cSFrederic Weisbecker 687391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 68819c92399SKees Cook bool "Enable per-task storage I/O accounting" 689391dc69cSFrederic Weisbecker depends on TASK_XACCT 690391dc69cSFrederic Weisbecker help 691391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 692391dc69cSFrederic Weisbecker task has caused. 693391dc69cSFrederic Weisbecker 694391dc69cSFrederic Weisbecker Say N if unsure. 695391dc69cSFrederic Weisbecker 696eb414681SJohannes Weinerconfig PSI 697eb414681SJohannes Weiner bool "Pressure stall information tracking" 69898dfdd9eSRandy Dunlap select KERNFS 699eb414681SJohannes Weiner help 700eb414681SJohannes Weiner Collect metrics that indicate how overcommitted the CPU, memory, 701eb414681SJohannes Weiner and IO capacity are in the system. 702eb414681SJohannes Weiner 703eb414681SJohannes Weiner If you say Y here, the kernel will create /proc/pressure/ with the 704eb414681SJohannes Weiner pressure statistics files cpu, memory, and io. These will indicate 705eb414681SJohannes Weiner the share of walltime in which some or all tasks in the system are 706eb414681SJohannes Weiner delayed due to contention of the respective resource. 707eb414681SJohannes Weiner 7082ce7135aSJohannes Weiner In kernels with cgroup support, cgroups (cgroup2 only) will 7092ce7135aSJohannes Weiner have cpu.pressure, memory.pressure, and io.pressure files, 7102ce7135aSJohannes Weiner which aggregate pressure stalls for the grouped tasks only. 7112ce7135aSJohannes Weiner 712c3123552SMauro Carvalho Chehab For more details see Documentation/accounting/psi.rst. 713eb414681SJohannes Weiner 714eb414681SJohannes Weiner Say N if unsure. 715eb414681SJohannes Weiner 716e0c27447SJohannes Weinerconfig PSI_DEFAULT_DISABLED 717e0c27447SJohannes Weiner bool "Require boot parameter to enable pressure stall information tracking" 718e0c27447SJohannes Weiner default n 719e0c27447SJohannes Weiner depends on PSI 720e0c27447SJohannes Weiner help 721e0c27447SJohannes Weiner If set, pressure stall information tracking will be disabled 722428a1cb4SBaruch Siach per default but can be enabled through passing psi=1 on the 723428a1cb4SBaruch Siach kernel commandline during boot. 724e0c27447SJohannes Weiner 7257b2489d3SJohannes Weiner This feature adds some code to the task wakeup and sleep 7267b2489d3SJohannes Weiner paths of the scheduler. The overhead is too low to affect 7277b2489d3SJohannes Weiner common scheduling-intense workloads in practice (such as 7287b2489d3SJohannes Weiner webservers, memcache), but it does show up in artificial 7297b2489d3SJohannes Weiner scheduler stress tests, such as hackbench. 7307b2489d3SJohannes Weiner 7317b2489d3SJohannes Weiner If you are paranoid and not sure what the kernel will be 7327b2489d3SJohannes Weiner used for, say Y. 7337b2489d3SJohannes Weiner 7347b2489d3SJohannes Weiner Say N if unsure. 7357b2489d3SJohannes Weiner 736391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 737391dc69cSFrederic Weisbecker 7385c4991e2SFrederic Weisbeckerconfig CPU_ISOLATION 7395c4991e2SFrederic Weisbecker bool "CPU isolation" 74097577684SOleg Nesterov depends on SMP 7412c43838cSFrederic Weisbecker default y 7425c4991e2SFrederic Weisbecker help 7435c4991e2SFrederic Weisbecker Make sure that CPUs running critical tasks are not disturbed by 7445c4991e2SFrederic Weisbecker any source of "noise" such as unbound workqueues, timers, kthreads... 7452c43838cSFrederic Weisbecker Unbound jobs get offloaded to housekeeping CPUs. This is driven by 7462c43838cSFrederic Weisbecker the "isolcpus=" boot parameter. 7472c43838cSFrederic Weisbecker 7482c43838cSFrederic Weisbecker Say Y if unsure. 7495c4991e2SFrederic Weisbecker 7500af92d46SPaul E. McKenneysource "kernel/rcu/Kconfig" 751c903ff83SMike Travis 7521da177e4SLinus Torvaldsconfig IKCONFIG 753f2443ab6SRoss Biro tristate "Kernel .config support" 754a7f7f624SMasahiro Yamada help 7551da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 7561da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 7571da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 7581da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 7591da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 7601da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 7611da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 7621da177e4SLinus Torvalds /proc/config.gz if enabled (below). 7631da177e4SLinus Torvalds 7641da177e4SLinus Torvaldsconfig IKCONFIG_PROC 7651da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 7661da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 767a7f7f624SMasahiro Yamada help 7681da177e4SLinus Torvalds This option enables access to the kernel configuration file 7691da177e4SLinus Torvalds through /proc/config.gz. 7701da177e4SLinus Torvalds 771f7b101d3SJoel Fernandes (Google)config IKHEADERS 772f7b101d3SJoel Fernandes (Google) tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 773f7b101d3SJoel Fernandes (Google) depends on SYSFS 77443d8ce9dSJoel Fernandes (Google) help 775f7b101d3SJoel Fernandes (Google) This option enables access to the in-kernel headers that are generated during 776f7b101d3SJoel Fernandes (Google) the build process. These can be used to build eBPF tracing programs, 777f7b101d3SJoel Fernandes (Google) or similar programs. If you build the headers as a module, a module called 778f7b101d3SJoel Fernandes (Google) kheaders.ko is built which can be loaded on-demand to get access to headers. 77943d8ce9dSJoel Fernandes (Google) 780794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 781794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 7821c4b5ecbSChristoph Hellwig range 12 25 783f17a32e9SAdrian Bunk default 17 784361e9dfbSJosh Triplett depends on PRINTK 785794543a2SAlistair John Strachan help 78623b2899fSLuis R. Rodriguez Select the minimal kernel log buffer size as a power of 2. 78723b2899fSLuis R. Rodriguez The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 78823b2899fSLuis R. Rodriguez parameter, see below. Any higher size also might be forced 78923b2899fSLuis R. Rodriguez by "log_buf_len" boot parameter. 79023b2899fSLuis R. Rodriguez 791f17a32e9SAdrian Bunk Examples: 792f17a32e9SAdrian Bunk 17 => 128 KB 793f17a32e9SAdrian Bunk 16 => 64 KB 794f17a32e9SAdrian Bunk 15 => 32 KB 795f17a32e9SAdrian Bunk 14 => 16 KB 796794543a2SAlistair John Strachan 13 => 8 KB 797794543a2SAlistair John Strachan 12 => 4 KB 798794543a2SAlistair John Strachan 79923b2899fSLuis R. Rodriguezconfig LOG_CPU_MAX_BUF_SHIFT 80023b2899fSLuis R. Rodriguez int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 8012240a31dSGeert Uytterhoeven depends on SMP 80223b2899fSLuis R. Rodriguez range 0 21 80323b2899fSLuis R. Rodriguez default 0 if BASE_SMALL 804320bf431SYoann Congal default 12 805361e9dfbSJosh Triplett depends on PRINTK 80623b2899fSLuis R. Rodriguez help 80723b2899fSLuis R. Rodriguez This option allows to increase the default ring buffer size 80823b2899fSLuis R. Rodriguez according to the number of CPUs. The value defines the contribution 80923b2899fSLuis R. Rodriguez of each CPU as a power of 2. The used space is typically only few 81023b2899fSLuis R. Rodriguez lines however it might be much more when problems are reported, 81123b2899fSLuis R. Rodriguez e.g. backtraces. 81223b2899fSLuis R. Rodriguez 81323b2899fSLuis R. Rodriguez The increased size means that a new buffer has to be allocated and 81423b2899fSLuis R. Rodriguez the original static one is unused. It makes sense only on systems 81523b2899fSLuis R. Rodriguez with more CPUs. Therefore this value is used only when the sum of 81623b2899fSLuis R. Rodriguez contributions is greater than the half of the default kernel ring 81723b2899fSLuis R. Rodriguez buffer as defined by LOG_BUF_SHIFT. The default values are set 8180f7636e1SPaul Menzel so that more than 16 CPUs are needed to trigger the allocation. 81923b2899fSLuis R. Rodriguez 82023b2899fSLuis R. Rodriguez Also this option is ignored when "log_buf_len" kernel parameter is 82123b2899fSLuis R. Rodriguez used as it forces an exact (power of two) size of the ring buffer. 82223b2899fSLuis R. Rodriguez 82323b2899fSLuis R. Rodriguez The number of possible CPUs is used for this computation ignoring 8245e0d8d59SGeert Uytterhoeven hotplugging making the computation optimal for the worst case 8255e0d8d59SGeert Uytterhoeven scenario while allowing a simple algorithm to be used from bootup. 82623b2899fSLuis R. Rodriguez 82723b2899fSLuis R. Rodriguez Examples shift values and their meaning: 82823b2899fSLuis R. Rodriguez 17 => 128 KB for each CPU 82923b2899fSLuis R. Rodriguez 16 => 64 KB for each CPU 83023b2899fSLuis R. Rodriguez 15 => 32 KB for each CPU 83123b2899fSLuis R. Rodriguez 14 => 16 KB for each CPU 83223b2899fSLuis R. Rodriguez 13 => 8 KB for each CPU 83323b2899fSLuis R. Rodriguez 12 => 4 KB for each CPU 83423b2899fSLuis R. Rodriguez 83533701557SChris Downconfig PRINTK_INDEX 83633701557SChris Down bool "Printk indexing debugfs interface" 83733701557SChris Down depends on PRINTK && DEBUG_FS 83833701557SChris Down help 83933701557SChris Down Add support for indexing of all printk formats known at compile time 84033701557SChris Down at <debugfs>/printk/index/<module>. 84133701557SChris Down 84233701557SChris Down This can be used as part of maintaining daemons which monitor 84333701557SChris Down /dev/kmsg, as it permits auditing the printk formats present in a 84433701557SChris Down kernel, allowing detection of cases where monitored printks are 84533701557SChris Down changed or no longer present. 84633701557SChris Down 84733701557SChris Down There is no additional runtime cost to printk with this enabled. 84833701557SChris Down 8495cdc38f9SKAMEZAWA Hiroyuki# 8505cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 8515cdc38f9SKAMEZAWA Hiroyuki# 8525cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 8535cdc38f9SKAMEZAWA Hiroyuki bool 8545cdc38f9SKAMEZAWA Hiroyuki 85538ff87f7SStephen Boydconfig GENERIC_SCHED_CLOCK 85638ff87f7SStephen Boyd bool 85738ff87f7SStephen Boyd 85869842cbaSPatrick Bellasimenu "Scheduler features" 85969842cbaSPatrick Bellasi 86069842cbaSPatrick Bellasiconfig UCLAMP_TASK 86169842cbaSPatrick Bellasi bool "Enable utilization clamping for RT/FAIR tasks" 86269842cbaSPatrick Bellasi depends on CPU_FREQ_GOV_SCHEDUTIL 86369842cbaSPatrick Bellasi help 86469842cbaSPatrick Bellasi This feature enables the scheduler to track the clamped utilization 86569842cbaSPatrick Bellasi of each CPU based on RUNNABLE tasks scheduled on that CPU. 86669842cbaSPatrick Bellasi 86769842cbaSPatrick Bellasi With this option, the user can specify the min and max CPU 86869842cbaSPatrick Bellasi utilization allowed for RUNNABLE tasks. The max utilization defines 86969842cbaSPatrick Bellasi the maximum frequency a task should use while the min utilization 87069842cbaSPatrick Bellasi defines the minimum frequency it should use. 87169842cbaSPatrick Bellasi 87269842cbaSPatrick Bellasi Both min and max utilization clamp values are hints to the scheduler, 87369842cbaSPatrick Bellasi aiming at improving its frequency selection policy, but they do not 87469842cbaSPatrick Bellasi enforce or grant any specific bandwidth for tasks. 87569842cbaSPatrick Bellasi 87669842cbaSPatrick Bellasi If in doubt, say N. 87769842cbaSPatrick Bellasi 87869842cbaSPatrick Bellasiconfig UCLAMP_BUCKETS_COUNT 87969842cbaSPatrick Bellasi int "Number of supported utilization clamp buckets" 88069842cbaSPatrick Bellasi range 5 20 88169842cbaSPatrick Bellasi default 5 88269842cbaSPatrick Bellasi depends on UCLAMP_TASK 88369842cbaSPatrick Bellasi help 88469842cbaSPatrick Bellasi Defines the number of clamp buckets to use. The range of each bucket 88569842cbaSPatrick Bellasi will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 88669842cbaSPatrick Bellasi number of clamp buckets the finer their granularity and the higher 88769842cbaSPatrick Bellasi the precision of clamping aggregation and tracking at run-time. 88869842cbaSPatrick Bellasi 88969842cbaSPatrick Bellasi For example, with the minimum configuration value we will have 5 89069842cbaSPatrick Bellasi clamp buckets tracking 20% utilization each. A 25% boosted tasks will 89169842cbaSPatrick Bellasi be refcounted in the [20..39]% bucket and will set the bucket clamp 89269842cbaSPatrick Bellasi effective value to 25%. 89369842cbaSPatrick Bellasi If a second 30% boosted task should be co-scheduled on the same CPU, 89469842cbaSPatrick Bellasi that task will be refcounted in the same bucket of the first task and 89569842cbaSPatrick Bellasi it will boost the bucket clamp effective value to 30%. 89669842cbaSPatrick Bellasi The clamp effective value of a bucket is reset to its nominal value 89769842cbaSPatrick Bellasi (20% in the example above) when there are no more tasks refcounted in 89869842cbaSPatrick Bellasi that bucket. 89969842cbaSPatrick Bellasi 90069842cbaSPatrick Bellasi An additional boost/capping margin can be added to some tasks. In the 90169842cbaSPatrick Bellasi example above the 25% task will be boosted to 30% until it exits the 90269842cbaSPatrick Bellasi CPU. If that should be considered not acceptable on certain systems, 90369842cbaSPatrick Bellasi it's always possible to reduce the margin by increasing the number of 90469842cbaSPatrick Bellasi clamp buckets to trade off used memory for run-time tracking 90569842cbaSPatrick Bellasi precision. 90669842cbaSPatrick Bellasi 90769842cbaSPatrick Bellasi If in doubt, use the default value. 90869842cbaSPatrick Bellasi 90925c411fcSJohn Stultzconfig SCHED_PROXY_EXEC 91025c411fcSJohn Stultz bool "Proxy Execution" 91125c411fcSJohn Stultz # Avoid some build failures w/ PREEMPT_RT until it can be fixed 91225c411fcSJohn Stultz depends on !PREEMPT_RT 91325c411fcSJohn Stultz # Need to investigate how to inform sched_ext of split contexts 91425c411fcSJohn Stultz depends on !SCHED_CLASS_EXT 91525c411fcSJohn Stultz # Not particularly useful until we get to multi-rq proxying 91625c411fcSJohn Stultz depends on EXPERT 91725c411fcSJohn Stultz help 91825c411fcSJohn Stultz This option enables proxy execution, a mechanism for mutex-owning 91925c411fcSJohn Stultz tasks to inherit the scheduling context of higher priority waiters. 92025c411fcSJohn Stultz 92169842cbaSPatrick Bellasiendmenu 92269842cbaSPatrick Bellasi 923be3a7284SAndrea Arcangeli# 924be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler 925be3a7284SAndrea Arcangeli# balancing logic: 926be3a7284SAndrea Arcangeli# 927be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING 928be3a7284SAndrea Arcangeli bool 929be3a7284SAndrea Arcangeli 930be5e610cSPeter Zijlstra# 93172b252aeSMel Gorman# For architectures that prefer to flush all TLBs after a number of pages 93272b252aeSMel Gorman# are unmapped instead of sending one IPI per page to flush. The architecture 93372b252aeSMel Gorman# must provide guarantees on what happens if a clean TLB cache entry is 93472b252aeSMel Gorman# written after the unmap. Details are in mm/rmap.c near the check for 93572b252aeSMel Gorman# should_defer_flush. The architecture should also consider if the full flush 93672b252aeSMel Gorman# and the refill costs are offset by the savings of sending fewer IPIs. 93772b252aeSMel Gormanconfig ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 93872b252aeSMel Gorman bool 93972b252aeSMel Gorman 940c12d3362SArd Biesheuvelconfig CC_HAS_INT128 9413a7c7331SMasahiro Yamada def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 942c12d3362SArd Biesheuvel 943dee2b702SGustavo A. R. Silvaconfig CC_IMPLICIT_FALLTHROUGH 944dee2b702SGustavo A. R. Silva string 945158ea2d2SGustavo A. R. Silva default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 946dee2b702SGustavo A. R. Silva default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 947dee2b702SGustavo A. R. Silva 9483e00f580SKees Cook# Currently, disable gcc-10+ array-bounds globally. 9490da6e5fdSLinus Torvalds# It's still broken in gcc-13, so no upper bound yet. 9503e00f580SKees Cookconfig GCC10_NO_ARRAY_BOUNDS 9515a41237aSLinus Torvalds def_bool y 9525a41237aSLinus Torvalds 953f0be87c4SLinus Torvaldsconfig CC_NO_ARRAY_BOUNDS 954f0be87c4SLinus Torvalds bool 9558e5bd4eaSYury Norov default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 956f0be87c4SLinus Torvalds 95702153319SLinus Torvalds# Currently, disable -Wstringop-overflow for GCC globally. 95802153319SLinus Torvaldsconfig GCC_NO_STRINGOP_OVERFLOW 959a5e0ace0SGustavo A. R. Silva def_bool y 960a5e0ace0SGustavo A. R. Silva 961a5e0ace0SGustavo A. R. Silvaconfig CC_NO_STRINGOP_OVERFLOW 962a5e0ace0SGustavo A. R. Silva bool 96302153319SLinus Torvalds default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 964a5e0ace0SGustavo A. R. Silva 965a5e0ace0SGustavo A. R. Silvaconfig CC_STRINGOP_OVERFLOW 966a5e0ace0SGustavo A. R. Silva bool 967a5e0ace0SGustavo A. R. Silva default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 968a5e0ace0SGustavo A. R. Silva 96972b252aeSMel Gorman# 970be5e610cSPeter Zijlstra# For architectures that know their GCC __int128 support is sound 971be5e610cSPeter Zijlstra# 972be5e610cSPeter Zijlstraconfig ARCH_SUPPORTS_INT128 973be5e610cSPeter Zijlstra bool 974be5e610cSPeter Zijlstra 975be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions 976be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH. 977be3a7284SAndrea Arcangeli# 978be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY 979be3a7284SAndrea Arcangeli bool 980be3a7284SAndrea Arcangeli 981be3a7284SAndrea Arcangeliconfig NUMA_BALANCING 982be3a7284SAndrea Arcangeli bool "Memory placement aware NUMA scheduler" 983be3a7284SAndrea Arcangeli depends on ARCH_SUPPORTS_NUMA_BALANCING 984be3a7284SAndrea Arcangeli depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 985554b0f3cSSebastian Andrzej Siewior depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 986be3a7284SAndrea Arcangeli help 987be3a7284SAndrea Arcangeli This option adds support for automatic NUMA aware memory/task placement. 988be3a7284SAndrea Arcangeli The mechanism is quite primitive and is based on migrating memory when 9896d56a410SPaul Gortmaker it has references to the node the task is running on. 990be3a7284SAndrea Arcangeli 991be3a7284SAndrea Arcangeli This system will be inactive on UMA systems. 992be3a7284SAndrea Arcangeli 9936f7c97e8SAneesh Kumar K.Vconfig NUMA_BALANCING_DEFAULT_ENABLED 9946f7c97e8SAneesh Kumar K.V bool "Automatically enable NUMA aware memory/task placement" 9956f7c97e8SAneesh Kumar K.V default y 9966f7c97e8SAneesh Kumar K.V depends on NUMA_BALANCING 9976f7c97e8SAneesh Kumar K.V help 9986f7c97e8SAneesh Kumar K.V If set, automatic NUMA balancing will be enabled if running on a NUMA 9996f7c97e8SAneesh Kumar K.V machine. 10006f7c97e8SAneesh Kumar K.V 100121c690a3SSuren Baghdasaryanconfig SLAB_OBJ_EXT 100221c690a3SSuren Baghdasaryan bool 100321c690a3SSuren Baghdasaryan 100423964d2dSLi Zefanmenuconfig CGROUPS 10056341e62bSChristoph Jaeger bool "Control Group support" 10062bd59d48STejun Heo select KERNFS 1007ddbcc7e8SPaul Menage help 100823964d2dSLi Zefan This option adds support for grouping sets of processes together, for 10095cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 10105cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 10115cdc38f9SKAMEZAWA Hiroyuki See 1012d6a3b247SMauro Carvalho Chehab - Documentation/scheduler/sched-design-CFS.rst (CFS) 1013da82c92fSMauro Carvalho Chehab - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 101445ce80fbSLi Zefan and resource control) 1015ddbcc7e8SPaul Menage 1016ddbcc7e8SPaul Menage Say N if unsure. 1017ddbcc7e8SPaul Menage 101823964d2dSLi Zefanif CGROUPS 101923964d2dSLi Zefan 10203e32cb2eSJohannes Weinerconfig PAGE_COUNTER 10213e32cb2eSJohannes Weiner bool 10223e32cb2eSJohannes Weiner 10236a010a49STejun Heoconfig CGROUP_FAVOR_DYNMODS 10246a010a49STejun Heo bool "Favor dynamic modification latency reduction by default" 10256a010a49STejun Heo help 10266a010a49STejun Heo This option enables the "favordynmods" mount option by default 10276a010a49STejun Heo which reduces the latencies of dynamic cgroup modifications such 10286a010a49STejun Heo as task migrations and controller on/offs at the cost of making 10296a010a49STejun Heo hot path operations such as forks and exits more expensive. 10306a010a49STejun Heo 10316a010a49STejun Heo Say N if unsure. 10326a010a49STejun Heo 1033c255a458SAndrew Mortonconfig MEMCG 1034a0166ec4SJohannes Weiner bool "Memory controller" 10353e32cb2eSJohannes Weiner select PAGE_COUNTER 103679bd9814STejun Heo select EVENTFD 103721c690a3SSuren Baghdasaryan select SLAB_OBJ_EXT 1038fdc5001bSKirill A. Shutemov select VM_EVENT_COUNTERS 103900f0b825SBalbir Singh help 1040a0166ec4SJohannes Weiner Provides control over the memory footprint of tasks in a cgroup. 104100f0b825SBalbir Singh 104225352d2fSShakeel Buttconfig MEMCG_NMI_UNSAFE 104325352d2fSShakeel Butt bool 104425352d2fSShakeel Butt depends on MEMCG 104525352d2fSShakeel Butt depends on HAVE_NMI 104625352d2fSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 104725352d2fSShakeel Butt default y 104825352d2fSShakeel Butt 1049940b01fcSShakeel Buttconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1050940b01fcSShakeel Butt bool 1051940b01fcSShakeel Butt depends on MEMCG 1052940b01fcSShakeel Butt depends on HAVE_NMI 1053940b01fcSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1054940b01fcSShakeel Butt default y 1055940b01fcSShakeel Butt 1056e93d4166SRoman Gushchinconfig MEMCG_V1 1057e93d4166SRoman Gushchin bool "Legacy cgroup v1 memory controller" 1058c9929f0eSVlastimil Babka depends on MEMCG 1059e93d4166SRoman Gushchin default n 1060e93d4166SRoman Gushchin help 1061e93d4166SRoman Gushchin Legacy cgroup v1 memory controller which has been deprecated by 1062e93d4166SRoman Gushchin cgroup v2 implementation. The v1 is there for legacy applications 1063e93d4166SRoman Gushchin which haven't migrated to the new cgroup v2 interface yet. If you 1064e93d4166SRoman Gushchin do not have any such application then you are completely fine leaving 1065e93d4166SRoman Gushchin this option disabled. 1066e93d4166SRoman Gushchin 1067e93d4166SRoman Gushchin Please note that feature set of the legacy memory controller is likely 1068e93d4166SRoman Gushchin going to shrink due to deprecation process. New deployments with v1 1069e93d4166SRoman Gushchin controller are highly discouraged. 1070e93d4166SRoman Gushchin 1071fcb4824bSValdis Kletnieks Say N if unsure. 107284c07d11SKirill Tkhai 10736bf024e6SJohannes Weinerconfig BLK_CGROUP 10746bf024e6SJohannes Weiner bool "IO controller" 10756bf024e6SJohannes Weiner depends on BLOCK 10762bc64a20SAneesh Kumar K.V default n 1077a7f7f624SMasahiro Yamada help 10786bf024e6SJohannes Weiner Generic block IO controller cgroup interface. This is the common 10796bf024e6SJohannes Weiner cgroup interface which should be used by various IO controlling 10806bf024e6SJohannes Weiner policies. 10812bc64a20SAneesh Kumar K.V 10826bf024e6SJohannes Weiner Currently, CFQ IO scheduler uses it to recognize task groups and 10836bf024e6SJohannes Weiner control disk bandwidth allocation (proportional time slice allocation) 10846bf024e6SJohannes Weiner to such task groups. It is also used by bio throttling logic in 10856bf024e6SJohannes Weiner block layer to implement upper limit in IO rates on a device. 1086e5d1367fSStephane Eranian 10876bf024e6SJohannes Weiner This option only enables generic Block IO controller infrastructure. 10886bf024e6SJohannes Weiner One needs to also enable actual IO controlling logic/policy. For 10896bf024e6SJohannes Weiner enabling proportional weight division of disk bandwidth in CFQ, set 10907baf2199SKrzysztof Kozlowski CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 10916bf024e6SJohannes Weiner CONFIG_BLK_DEV_THROTTLING=y. 10926bf024e6SJohannes Weiner 1093da82c92fSMauro Carvalho Chehab See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 10946bf024e6SJohannes Weiner 10956bf024e6SJohannes Weinerconfig CGROUP_WRITEBACK 10966bf024e6SJohannes Weiner bool 10976bf024e6SJohannes Weiner depends on MEMCG && BLK_CGROUP 10986bf024e6SJohannes Weiner default y 1099e5d1367fSStephane Eranian 11007c941438SDhaval Gianimenuconfig CGROUP_SCHED 1101a0166ec4SJohannes Weiner bool "CPU controller" 11027c941438SDhaval Giani default n 11037c941438SDhaval Giani help 11047c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 11057c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 11067c941438SDhaval Giani tasks. 11077c941438SDhaval Giani 11087c941438SDhaval Gianiif CGROUP_SCHED 1109e179e80cSTejun Heoconfig GROUP_SCHED_WEIGHT 1110e179e80cSTejun Heo def_bool n 1111e179e80cSTejun Heo 1112ddceadceSTejun Heoconfig GROUP_SCHED_BANDWIDTH 1113ddceadceSTejun Heo def_bool n 1114ddceadceSTejun Heo 11157c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 11167c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 11177c941438SDhaval Giani depends on CGROUP_SCHED 1118e179e80cSTejun Heo select GROUP_SCHED_WEIGHT 11197c941438SDhaval Giani default CGROUP_SCHED 11207c941438SDhaval Giani 1121ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 1122ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1123ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 1124ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 1125ab84d31eSPaul Turner default n 1126ab84d31eSPaul Turner help 1127ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 1128ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 1129ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 1130ab84d31eSPaul Turner restriction. 1131d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-bwc.rst for more information. 1132ab84d31eSPaul Turner 11337c941438SDhaval Gianiconfig RT_GROUP_SCHED 11347c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 11357c941438SDhaval Giani depends on CGROUP_SCHED 11367c941438SDhaval Giani default n 11377c941438SDhaval Giani help 11387c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 113932bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 11407c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 11417c941438SDhaval Giani realtime bandwidth for them. 1142d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-rt-group.rst for more information. 11437c941438SDhaval Giani 1144e34e0131SMichal Koutnýconfig RT_GROUP_SCHED_DEFAULT_DISABLED 1145e34e0131SMichal Koutný bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1146e34e0131SMichal Koutný depends on RT_GROUP_SCHED 1147e34e0131SMichal Koutný default n 1148e34e0131SMichal Koutný help 1149e34e0131SMichal Koutný When set, the RT group scheduling is disabled by default. The option 1150e34e0131SMichal Koutný is in inverted form so that mere RT_GROUP_SCHED enables the group 1151e34e0131SMichal Koutný scheduling. 1152e34e0131SMichal Koutný 1153e34e0131SMichal Koutný Say N if unsure. 1154e34e0131SMichal Koutný 115581951366STejun Heoconfig EXT_GROUP_SCHED 115681951366STejun Heo bool 115781951366STejun Heo depends on SCHED_CLASS_EXT && CGROUP_SCHED 115881951366STejun Heo select GROUP_SCHED_WEIGHT 1159ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 116081951366STejun Heo default y 116181951366STejun Heo 11627c941438SDhaval Gianiendif #CGROUP_SCHED 11637c941438SDhaval Giani 1164af7f588dSMathieu Desnoyersconfig SCHED_MM_CID 1165af7f588dSMathieu Desnoyers def_bool y 1166af7f588dSMathieu Desnoyers depends on SMP && RSEQ 1167af7f588dSMathieu Desnoyers 11682480c093SPatrick Bellasiconfig UCLAMP_TASK_GROUP 11692480c093SPatrick Bellasi bool "Utilization clamping per group of tasks" 11702480c093SPatrick Bellasi depends on CGROUP_SCHED 11712480c093SPatrick Bellasi depends on UCLAMP_TASK 11722480c093SPatrick Bellasi default n 11732480c093SPatrick Bellasi help 11742480c093SPatrick Bellasi This feature enables the scheduler to track the clamped utilization 11752480c093SPatrick Bellasi of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 11762480c093SPatrick Bellasi 11772480c093SPatrick Bellasi When this option is enabled, the user can specify a min and max 11782480c093SPatrick Bellasi CPU bandwidth which is allowed for each single task in a group. 11792480c093SPatrick Bellasi The max bandwidth allows to clamp the maximum frequency a task 11802480c093SPatrick Bellasi can use, while the min bandwidth allows to define a minimum 11812480c093SPatrick Bellasi frequency a task will always use. 11822480c093SPatrick Bellasi 11832480c093SPatrick Bellasi When task group based utilization clamping is enabled, an eventually 11842480c093SPatrick Bellasi specified task-specific clamp value is constrained by the cgroup 11852480c093SPatrick Bellasi specified clamp value. Both minimum and maximum task clamping cannot 11862480c093SPatrick Bellasi be bigger than the corresponding clamping defined at task group level. 11872480c093SPatrick Bellasi 11882480c093SPatrick Bellasi If in doubt, say N. 11892480c093SPatrick Bellasi 11906bf024e6SJohannes Weinerconfig CGROUP_PIDS 11916bf024e6SJohannes Weiner bool "PIDs controller" 11926bf024e6SJohannes Weiner help 11936bf024e6SJohannes Weiner Provides enforcement of process number limits in the scope of a 11946bf024e6SJohannes Weiner cgroup. Any attempt to fork more processes than is allowed in the 11956bf024e6SJohannes Weiner cgroup will fail. PIDs are fundamentally a global resource because it 11966bf024e6SJohannes Weiner is fairly trivial to reach PID exhaustion before you reach even a 11976bf024e6SJohannes Weiner conservative kmemcg limit. As a result, it is possible to grind a 11986bf024e6SJohannes Weiner system to halt without being limited by other cgroup policies. The 11996cc578dfSParav Pandit PIDs controller is designed to stop this from happening. 12006bf024e6SJohannes Weiner 12016bf024e6SJohannes Weiner It should be noted that organisational operations (such as attaching 120298076833SJonathan Neuschäfer to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 12036bf024e6SJohannes Weiner since the PIDs limit only affects a process's ability to fork, not to 12046bf024e6SJohannes Weiner attach to a cgroup. 12056bf024e6SJohannes Weiner 120639d3e758SParav Panditconfig CGROUP_RDMA 120739d3e758SParav Pandit bool "RDMA controller" 120839d3e758SParav Pandit help 120939d3e758SParav Pandit Provides enforcement of RDMA resources defined by IB stack. 121039d3e758SParav Pandit It is fairly easy for consumers to exhaust RDMA resources, which 121139d3e758SParav Pandit can result into resource unavailability to other consumers. 121239d3e758SParav Pandit RDMA controller is designed to stop this from happening. 121339d3e758SParav Pandit Attaching processes with active RDMA resources to the cgroup 121439d3e758SParav Pandit hierarchy is allowed even if can cross the hierarchy's limit. 121539d3e758SParav Pandit 1216b168ed45SMaarten Lankhorstconfig CGROUP_DMEM 1217b168ed45SMaarten Lankhorst bool "Device memory controller (DMEM)" 1218e33b5149SMaxime Ripard select PAGE_COUNTER 1219b168ed45SMaarten Lankhorst help 1220b168ed45SMaarten Lankhorst The DMEM controller allows compatible devices to restrict device 1221b168ed45SMaarten Lankhorst memory usage based on the cgroup hierarchy. 1222b168ed45SMaarten Lankhorst 1223b168ed45SMaarten Lankhorst As an example, it allows you to restrict VRAM usage for applications 1224b168ed45SMaarten Lankhorst in the DRM subsystem. 1225b168ed45SMaarten Lankhorst 12266bf024e6SJohannes Weinerconfig CGROUP_FREEZER 12276bf024e6SJohannes Weiner bool "Freezer controller" 12286bf024e6SJohannes Weiner help 12296bf024e6SJohannes Weiner Provides a way to freeze and unfreeze all tasks in a 12306bf024e6SJohannes Weiner cgroup. 12316bf024e6SJohannes Weiner 1232489c2a20SJohannes Weiner This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1233489c2a20SJohannes Weiner controller includes important in-kernel memory consumers per default. 1234489c2a20SJohannes Weiner 1235489c2a20SJohannes Weiner If you're using cgroup2, say N. 1236489c2a20SJohannes Weiner 12376bf024e6SJohannes Weinerconfig CGROUP_HUGETLB 12386bf024e6SJohannes Weiner bool "HugeTLB controller" 12396bf024e6SJohannes Weiner depends on HUGETLB_PAGE 12406bf024e6SJohannes Weiner select PAGE_COUNTER 1241afc24d49SVivek Goyal default n 12426bf024e6SJohannes Weiner help 12436bf024e6SJohannes Weiner Provides a cgroup controller for HugeTLB pages. 12446bf024e6SJohannes Weiner When you enable this, you can put a per cgroup limit on HugeTLB usage. 12456bf024e6SJohannes Weiner The limit is enforced during page fault. Since HugeTLB doesn't 12466bf024e6SJohannes Weiner support page reclaim, enforcing the limit at page fault time implies 12476bf024e6SJohannes Weiner that, the application will get SIGBUS signal if it tries to access 12486bf024e6SJohannes Weiner HugeTLB pages beyond its limit. This requires the application to know 12496bf024e6SJohannes Weiner beforehand how much HugeTLB pages it would require for its use. The 12506bf024e6SJohannes Weiner control group is tracked in the third page lru pointer. This means 12516bf024e6SJohannes Weiner that we cannot use the controller with huge page less than 3 pages. 1252afc24d49SVivek Goyal 12536bf024e6SJohannes Weinerconfig CPUSETS 12546bf024e6SJohannes Weiner bool "Cpuset controller" 1255e1d4eeecSNicolas Pitre depends on SMP 1256bf9850f6SKuan-Wei Chiu select UNION_FIND 12576bf024e6SJohannes Weiner help 12586bf024e6SJohannes Weiner This option will let you create and manage CPUSETs which 12596bf024e6SJohannes Weiner allow dynamically partitioning a system into sets of CPUs and 12606bf024e6SJohannes Weiner Memory Nodes and assigning tasks to run only within those sets. 12616bf024e6SJohannes Weiner This is primarily useful on large SMP or NUMA systems. 1262afc24d49SVivek Goyal 12636bf024e6SJohannes Weiner Say N if unsure. 1264afc24d49SVivek Goyal 12651abab1baSChen Ridongconfig CPUSETS_V1 12661abab1baSChen Ridong bool "Legacy cgroup v1 cpusets controller" 12671abab1baSChen Ridong depends on CPUSETS 12681abab1baSChen Ridong default n 12691abab1baSChen Ridong help 12701abab1baSChen Ridong Legacy cgroup v1 cpusets controller which has been deprecated by 12711abab1baSChen Ridong cgroup v2 implementation. The v1 is there for legacy applications 1272dae68fbaSMichal Koutný which haven't migrated to the new cgroup v2 interface yet. Legacy 1273dae68fbaSMichal Koutný interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 12741abab1baSChen Ridong do not have any such application then you are completely fine leaving 12751abab1baSChen Ridong this option disabled. 12761abab1baSChen Ridong 12771abab1baSChen Ridong Say N if unsure. 12781abab1baSChen Ridong 12796bf024e6SJohannes Weinerconfig PROC_PID_CPUSET 12806bf024e6SJohannes Weiner bool "Include legacy /proc/<pid>/cpuset file" 1281dae68fbaSMichal Koutný depends on CPUSETS_V1 128289e9b9e0STejun Heo default y 128389e9b9e0STejun Heo 12846bf024e6SJohannes Weinerconfig CGROUP_DEVICE 12856bf024e6SJohannes Weiner bool "Device controller" 12866bf024e6SJohannes Weiner help 12876bf024e6SJohannes Weiner Provides a cgroup controller implementing whitelists for 12886bf024e6SJohannes Weiner devices which a process in the cgroup can mknod or open. 12896bf024e6SJohannes Weiner 12906bf024e6SJohannes Weinerconfig CGROUP_CPUACCT 12916bf024e6SJohannes Weiner bool "Simple CPU accounting controller" 12926bf024e6SJohannes Weiner help 12936bf024e6SJohannes Weiner Provides a simple controller for monitoring the 12946bf024e6SJohannes Weiner total CPU consumed by the tasks in a cgroup. 12956bf024e6SJohannes Weiner 12966bf024e6SJohannes Weinerconfig CGROUP_PERF 12976bf024e6SJohannes Weiner bool "Perf controller" 12986bf024e6SJohannes Weiner depends on PERF_EVENTS 12996bf024e6SJohannes Weiner help 13006bf024e6SJohannes Weiner This option extends the perf per-cpu mode to restrict monitoring 13016bf024e6SJohannes Weiner to threads which belong to the cgroup specified and run on the 13026546b19fSNamhyung Kim designated cpu. Or this can be used to have cgroup ID in samples 13036546b19fSNamhyung Kim so that it can monitor performance events among cgroups. 13046bf024e6SJohannes Weiner 13056bf024e6SJohannes Weiner Say N if unsure. 13066bf024e6SJohannes Weiner 130730070984SDaniel Mackconfig CGROUP_BPF 130830070984SDaniel Mack bool "Support for eBPF programs attached to cgroups" 1309483c4933SAndy Lutomirski depends on BPF_SYSCALL 1310483c4933SAndy Lutomirski select SOCK_CGROUP_DATA 131130070984SDaniel Mack help 131230070984SDaniel Mack Allow attaching eBPF programs to a cgroup using the bpf(2) 131330070984SDaniel Mack syscall command BPF_PROG_ATTACH. 131430070984SDaniel Mack 131530070984SDaniel Mack In which context these programs are accessed depends on the type 131630070984SDaniel Mack of attachment. For instance, programs that are attached using 131730070984SDaniel Mack BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 131830070984SDaniel Mack inet sockets. 131930070984SDaniel Mack 1320a72232eaSVipin Sharmaconfig CGROUP_MISC 1321a72232eaSVipin Sharma bool "Misc resource controller" 1322a72232eaSVipin Sharma default n 1323a72232eaSVipin Sharma help 1324a72232eaSVipin Sharma Provides a controller for miscellaneous resources on a host. 1325a72232eaSVipin Sharma 1326a72232eaSVipin Sharma Miscellaneous scalar resources are the resources on the host system 1327a72232eaSVipin Sharma which cannot be abstracted like the other cgroups. This controller 1328a72232eaSVipin Sharma tracks and limits the miscellaneous resources used by a process 1329a72232eaSVipin Sharma attached to a cgroup hierarchy. 1330a72232eaSVipin Sharma 1331a72232eaSVipin Sharma For more information, please check misc cgroup section in 1332a72232eaSVipin Sharma /Documentation/admin-guide/cgroup-v2.rst. 1333a72232eaSVipin Sharma 13346bf024e6SJohannes Weinerconfig CGROUP_DEBUG 133523b0be48SWaiman Long bool "Debug controller" 13366bf024e6SJohannes Weiner default n 133723b0be48SWaiman Long depends on DEBUG_KERNEL 13386bf024e6SJohannes Weiner help 13396bf024e6SJohannes Weiner This option enables a simple controller that exports 134023b0be48SWaiman Long debugging information about the cgroups framework. This 134123b0be48SWaiman Long controller is for control cgroup debugging only. Its 134223b0be48SWaiman Long interfaces are not stable. 13436bf024e6SJohannes Weiner 13446bf024e6SJohannes Weiner Say N. 13456bf024e6SJohannes Weiner 134673b35147SArnd Bergmannconfig SOCK_CGROUP_DATA 134773b35147SArnd Bergmann bool 134873b35147SArnd Bergmann default n 134973b35147SArnd Bergmann 135023964d2dSLi Zefanendif # CGROUPS 1351c077719bSKAMEZAWA Hiroyuki 13528dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 13536a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 13542813893fSIulia Manda depends on MULTIUSER 13556a108a14SDavid Rientjes default !EXPERT 1356c5289a69SPavel Emelyanov help 1357c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 1358c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 1359c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 1360c5289a69SPavel Emelyanov different namespaces. 1361c5289a69SPavel Emelyanov 13628dd2a82cSDaniel Lezcanoif NAMESPACES 13638dd2a82cSDaniel Lezcano 136458bfdd6dSPavel Emelyanovconfig UTS_NS 136558bfdd6dSPavel Emelyanov bool "UTS namespace" 136617a6d441SDaniel Lezcano default y 136758bfdd6dSPavel Emelyanov help 136858bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 136958bfdd6dSPavel Emelyanov uname() system call 137058bfdd6dSPavel Emelyanov 1371769071acSAndrei Vaginconfig TIME_NS 1372769071acSAndrei Vagin bool "TIME namespace" 1373bad53ae2SThomas Weißschuh depends on GENERIC_GETTIMEOFDAY 1374769071acSAndrei Vagin default y 1375769071acSAndrei Vagin help 1376769071acSAndrei Vagin In this namespace boottime and monotonic clocks can be set. 1377769071acSAndrei Vagin The time will keep going with the same pace. 1378769071acSAndrei Vagin 1379ae5e1b22SPavel Emelyanovconfig IPC_NS 1380ae5e1b22SPavel Emelyanov bool "IPC namespace" 13818dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 138217a6d441SDaniel Lezcano default y 1383ae5e1b22SPavel Emelyanov help 1384ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 1385614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 1386ae5e1b22SPavel Emelyanov 1387aee16ce7SPavel Emelyanovconfig USER_NS 138819c92399SKees Cook bool "User namespace" 13895673a94cSEric W. Biederman default n 1390aee16ce7SPavel Emelyanov help 1391aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 1392aee16ce7SPavel Emelyanov to provide different user info for different servers. 1393e11f0ae3SEric W. Biederman 1394e11f0ae3SEric W. Biederman When user namespaces are enabled in the kernel it is 1395d886f4e4SJohannes Weiner recommended that the MEMCG option also be enabled and that 1396d886f4e4SJohannes Weiner user-space use the memory control groups to limit the amount 1397d886f4e4SJohannes Weiner of memory a memory unprivileged users can use. 1398e11f0ae3SEric W. Biederman 1399aee16ce7SPavel Emelyanov If unsure, say N. 1400aee16ce7SPavel Emelyanov 140174bd59bbSPavel Emelyanovconfig PID_NS 14029bd38c2cSDaniel Lezcano bool "PID Namespaces" 140317a6d441SDaniel Lezcano default y 140474bd59bbSPavel Emelyanov help 140512d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 1406692105b8SMatt LaPlante processes with the same pid as long as they are in different 140774bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 140874bd59bbSPavel Emelyanov 1409d6eb633fSMatt Helsleyconfig NET_NS 1410d6eb633fSMatt Helsley bool "Network namespace" 14118dd2a82cSDaniel Lezcano depends on NET 141217a6d441SDaniel Lezcano default y 1413d6eb633fSMatt Helsley help 1414d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 1415d6eb633fSMatt Helsley of the network stack. 1416d6eb633fSMatt Helsley 14178dd2a82cSDaniel Lezcanoendif # NAMESPACES 14188dd2a82cSDaniel Lezcano 14195cb366bbSAdrian Reberconfig CHECKPOINT_RESTORE 14205cb366bbSAdrian Reber bool "Checkpoint/restore support" 142130341ec9SRen Zhijie depends on PROC_FS 14225cb366bbSAdrian Reber select PROC_CHILDREN 1423bfe3911aSChris Wilson select KCMP 14245cb366bbSAdrian Reber default n 14255cb366bbSAdrian Reber help 14265cb366bbSAdrian Reber Enables additional kernel features in a sake of checkpoint/restore. 14275cb366bbSAdrian Reber In particular it adds auxiliary prctl codes to setup process text, 14285cb366bbSAdrian Reber data and heap segment sizes, and a few additional /proc filesystem 14295cb366bbSAdrian Reber entries. 14305cb366bbSAdrian Reber 14315cb366bbSAdrian Reber If unsure, say N here. 14325cb366bbSAdrian Reber 14335091faa4SMike Galbraithconfig SCHED_AUTOGROUP 14345091faa4SMike Galbraith bool "Automatic process group scheduling" 14355091faa4SMike Galbraith select CGROUPS 14365091faa4SMike Galbraith select CGROUP_SCHED 14375091faa4SMike Galbraith select FAIR_GROUP_SCHED 14385091faa4SMike Galbraith help 14395091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 14405091faa4SMike Galbraith automatically creating and populating task groups. This separation 14415091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 14425091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 14435091faa4SMike Galbraith upon task session. 14445091faa4SMike Galbraith 14457af37becSDaniel Lezcanoconfig RELAY 14467af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 144726b5679eSPeter Zijlstra select IRQ_WORK 14487af37becSDaniel Lezcano help 14497af37becSDaniel Lezcano This option enables support for relay interface support in 14507af37becSDaniel Lezcano certain file systems (such as debugfs). 14517af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 14527af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 14537af37becSDaniel Lezcano user space. 14547af37becSDaniel Lezcano 14557af37becSDaniel Lezcano If unsure, say N. 14567af37becSDaniel Lezcano 1457f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1458f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1459f991633dSDimitri Gorokhovik help 1460f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1461f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1462f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1463f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 14648c27ceffSMauro Carvalho Chehab etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1465f991633dSDimitri Gorokhovik 1466f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1467f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1468f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1469f991633dSDimitri Gorokhovik 1470f991633dSDimitri Gorokhovik If unsure say Y. 1471f991633dSDimitri Gorokhovik 1472c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1473c33df4eaSJean-Paul Saman 1474dbec4866SSam Ravnborgsource "usr/Kconfig" 1475dbec4866SSam Ravnborg 1476c33df4eaSJean-Paul Samanendif 1477c33df4eaSJean-Paul Saman 147876db5a27SMasami Hiramatsuconfig BOOT_CONFIG 147976db5a27SMasami Hiramatsu bool "Boot config support" 1480a2a9d67aSMasami Hiramatsu select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 148176db5a27SMasami Hiramatsu help 148276db5a27SMasami Hiramatsu Extra boot config allows system admin to pass a config file as 148376db5a27SMasami Hiramatsu complemental extension of kernel cmdline when booting. 14840947db01SMasami Hiramatsu The boot config file must be attached at the end of initramfs 148585c46b78SMasami Hiramatsu with checksum, size and magic word. 14860947db01SMasami Hiramatsu See <file:Documentation/admin-guide/bootconfig.rst> for details. 148776db5a27SMasami Hiramatsu 148876db5a27SMasami Hiramatsu If unsure, say Y. 148976db5a27SMasami Hiramatsu 1490b743852cSPaul E. McKenneyconfig BOOT_CONFIG_FORCE 1491b743852cSPaul E. McKenney bool "Force unconditional bootconfig processing" 1492b743852cSPaul E. McKenney depends on BOOT_CONFIG 14936ded8a28SPaul E. McKenney default y if BOOT_CONFIG_EMBED 1494b743852cSPaul E. McKenney help 1495b743852cSPaul E. McKenney With this Kconfig option set, BOOT_CONFIG processing is carried 1496b743852cSPaul E. McKenney out even when the "bootconfig" kernel-boot parameter is omitted. 1497b743852cSPaul E. McKenney In fact, with this Kconfig option set, there is no way to 1498b743852cSPaul E. McKenney make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1499b743852cSPaul E. McKenney parameters. 1500b743852cSPaul E. McKenney 1501b743852cSPaul E. McKenney If unsure, say N. 1502b743852cSPaul E. McKenney 1503a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED 1504a2a9d67aSMasami Hiramatsu bool "Embed bootconfig file in the kernel" 1505a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG 1506a2a9d67aSMasami Hiramatsu help 1507a2a9d67aSMasami Hiramatsu Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1508a2a9d67aSMasami Hiramatsu kernel. Usually, the bootconfig file is loaded with the initrd 1509a2a9d67aSMasami Hiramatsu image. But if the system doesn't support initrd, this option will 1510a2a9d67aSMasami Hiramatsu help you by embedding a bootconfig file while building the kernel. 1511a2a9d67aSMasami Hiramatsu 1512a2a9d67aSMasami Hiramatsu If unsure, say N. 1513a2a9d67aSMasami Hiramatsu 1514a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED_FILE 1515a2a9d67aSMasami Hiramatsu string "Embedded bootconfig file path" 1516a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG_EMBED 1517a2a9d67aSMasami Hiramatsu help 1518a2a9d67aSMasami Hiramatsu Specify a bootconfig file which will be embedded to the kernel. 1519a2a9d67aSMasami Hiramatsu This bootconfig will be used if there is no initrd or no other 1520a2a9d67aSMasami Hiramatsu bootconfig in the initrd. 1521a2a9d67aSMasami Hiramatsu 1522032a7302SDouglas Andersonconfig CMDLINE_LOG_WRAP_IDEAL_LEN 1523032a7302SDouglas Anderson int "Length to try to wrap the cmdline when logged at boot" 1524032a7302SDouglas Anderson default 1021 1525032a7302SDouglas Anderson range 0 1021 1526032a7302SDouglas Anderson help 1527032a7302SDouglas Anderson At boot time, the kernel command line is logged to the console. 1528032a7302SDouglas Anderson The log message will start with the prefix "Kernel command line: ". 1529032a7302SDouglas Anderson The log message will attempt to be wrapped (split into multiple log 1530032a7302SDouglas Anderson messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1531032a7302SDouglas Anderson If wrapping happens, each log message will start with the prefix and 1532032a7302SDouglas Anderson all but the last message will end with " \". Messages may exceed the 1533032a7302SDouglas Anderson ideal length if a place to wrap isn't found before the specified 1534032a7302SDouglas Anderson number of characters. 1535032a7302SDouglas Anderson 1536032a7302SDouglas Anderson A value of 0 disables wrapping, though be warned that the maximum 1537032a7302SDouglas Anderson length of a log message (1021 characters) may cause the cmdline to 1538032a7302SDouglas Anderson be truncated. 1539032a7302SDouglas Anderson 15401274aea1SDavid Disseldorpconfig INITRAMFS_PRESERVE_MTIME 15411274aea1SDavid Disseldorp bool "Preserve cpio archive mtimes in initramfs" 154274792608SGeert Uytterhoeven depends on BLK_DEV_INITRD 15431274aea1SDavid Disseldorp default y 15441274aea1SDavid Disseldorp help 15451274aea1SDavid Disseldorp Each entry in an initramfs cpio archive carries an mtime value. When 15461274aea1SDavid Disseldorp enabled, extracted cpio items take this mtime, with directory mtime 15471274aea1SDavid Disseldorp setting deferred until after creation of any child entries. 15481274aea1SDavid Disseldorp 15491274aea1SDavid Disseldorp If unsure, say Y. 15501274aea1SDavid Disseldorp 155183c0b272SDavid Disseldorpconfig INITRAMFS_TEST 155283c0b272SDavid Disseldorp bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 155383c0b272SDavid Disseldorp depends on BLK_DEV_INITRD && KUNIT=y 155483c0b272SDavid Disseldorp default KUNIT_ALL_TESTS 155583c0b272SDavid Disseldorp help 155683c0b272SDavid Disseldorp Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 155783c0b272SDavid Disseldorp 1558877417e6SArnd Bergmannchoice 1559877417e6SArnd Bergmann prompt "Compiler optimization level" 15602cc3ce24SUlf Magnusson default CC_OPTIMIZE_FOR_PERFORMANCE 1561877417e6SArnd Bergmann 1562877417e6SArnd Bergmannconfig CC_OPTIMIZE_FOR_PERFORMANCE 156315f5db60SMasahiro Yamada bool "Optimize for performance (-O2)" 1564877417e6SArnd Bergmann help 1565877417e6SArnd Bergmann This is the default optimization level for the kernel, building 1566877417e6SArnd Bergmann with the "-O2" compiler flag for best performance and most 1567877417e6SArnd Bergmann helpful compile-time warnings. 1568877417e6SArnd Bergmann 1569c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 157015f5db60SMasahiro Yamada bool "Optimize for size (-Os)" 1571c45b4f1fSLinus Torvalds help 1572ce3b487fSMasahiro Yamada Choosing this option will pass "-Os" to your compiler resulting 1573ce3b487fSMasahiro Yamada in a smaller kernel. 1574c45b4f1fSLinus Torvalds 1575877417e6SArnd Bergmannendchoice 1576877417e6SArnd Bergmann 15775d20ee31SNicholas Pigginconfig HAVE_LD_DEAD_CODE_DATA_ELIMINATION 15785d20ee31SNicholas Piggin bool 15795d20ee31SNicholas Piggin help 15805d20ee31SNicholas Piggin This requires that the arch annotates or otherwise protects 15815d20ee31SNicholas Piggin its external entry points from being discarded. Linker scripts 15825d20ee31SNicholas Piggin must also merge .text.*, .data.*, and .bss.* correctly into 15835d20ee31SNicholas Piggin output sections. Care must be taken not to pull in unrelated 15845d20ee31SNicholas Piggin sections (e.g., '.text.init'). Typically '.' in section names 15855d20ee31SNicholas Piggin is used to distinguish them from label names / C identifiers. 15865d20ee31SNicholas Piggin 15875d20ee31SNicholas Pigginconfig LD_DEAD_CODE_DATA_ELIMINATION 15885d20ee31SNicholas Piggin bool "Dead code and data elimination (EXPERIMENTAL)" 15895d20ee31SNicholas Piggin depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 15905d20ee31SNicholas Piggin depends on EXPERT 1591e85d1d65SMasahiro Yamada depends on $(cc-option,-ffunction-sections -fdata-sections) 1592e85d1d65SMasahiro Yamada depends on $(ld-option,--gc-sections) 15935d20ee31SNicholas Piggin help 15948b9d2712SMasahiro Yamada Enable this if you want to do dead code and data elimination with 15958b9d2712SMasahiro Yamada the linker by compiling with -ffunction-sections -fdata-sections, 15968b9d2712SMasahiro Yamada and linking with --gc-sections. 15975d20ee31SNicholas Piggin 15985d20ee31SNicholas Piggin This can reduce on disk and in-memory size of the kernel 15995d20ee31SNicholas Piggin code and static data, particularly for small configs and 16005d20ee31SNicholas Piggin on small systems. This has the possibility of introducing 16015d20ee31SNicholas Piggin silently broken kernel if the required annotations are not 16025d20ee31SNicholas Piggin present. This option is not well tested yet, so use at your 16035d20ee31SNicholas Piggin own risk. 16045d20ee31SNicholas Piggin 160559612b24SNathan Chancellorconfig LD_ORPHAN_WARN 160659612b24SNathan Chancellor def_bool y 160759612b24SNathan Chancellor depends on ARCH_WANT_LD_ORPHAN_WARN 160859612b24SNathan Chancellor depends on $(ld-option,--orphan-handling=warn) 1609e1789d7cSXin Li depends on $(ld-option,--orphan-handling=error) 1610e1789d7cSXin Li 1611e1789d7cSXin Liconfig LD_ORPHAN_WARN_LEVEL 1612e1789d7cSXin Li string 1613e1789d7cSXin Li depends on LD_ORPHAN_WARN 1614e1789d7cSXin Li default "error" if WERROR 1615e1789d7cSXin Li default "warn" 161659612b24SNathan Chancellor 16170847062aSRandy Dunlapconfig SYSCTL 16180847062aSRandy Dunlap bool 16190847062aSRandy Dunlap 1620657a5209SMike Frysingerconfig HAVE_UID16 1621657a5209SMike Frysinger bool 1622657a5209SMike Frysinger 1623657a5209SMike Frysingerconfig SYSCTL_EXCEPTION_TRACE 1624657a5209SMike Frysinger bool 1625657a5209SMike Frysinger help 1626657a5209SMike Frysinger Enable support for /proc/sys/debug/exception-trace. 1627657a5209SMike Frysinger 1628657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_NO_WARN 1629657a5209SMike Frysinger bool 1630657a5209SMike Frysinger help 1631657a5209SMike Frysinger Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1632657a5209SMike Frysinger Allows arch to define/use @no_unaligned_warning to possibly warn 1633657a5209SMike Frysinger about unaligned access emulation going on under the hood. 1634657a5209SMike Frysinger 1635657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_ALLOW 1636657a5209SMike Frysinger bool 1637657a5209SMike Frysinger help 1638657a5209SMike Frysinger Enable support for /proc/sys/kernel/unaligned-trap 1639657a5209SMike Frysinger Allows arches to define/use @unaligned_enabled to runtime toggle 1640657a5209SMike Frysinger the unaligned access emulation. 1641657a5209SMike Frysinger see arch/parisc/kernel/unaligned.c for reference 1642657a5209SMike Frysinger 1643c443279aSChristian Braunerconfig SYSFS_SYSCALL 1644c443279aSChristian Brauner bool "Sysfs syscall support" 1645c443279aSChristian Brauner default n 1646c443279aSChristian Brauner help 1647c443279aSChristian Brauner sys_sysfs is an obsolete system call no longer supported in libc. 1648c443279aSChristian Brauner Note that disabling this option is more secure but might break 1649c443279aSChristian Brauner compatibility with some systems. 1650c443279aSChristian Brauner 1651c443279aSChristian Brauner If unsure say N here. 1652c443279aSChristian Brauner 1653657a5209SMike Frysingerconfig HAVE_PCSPKR_PLATFORM 1654657a5209SMike Frysinger bool 1655657a5209SMike Frysinger 16566a108a14SDavid Rientjesmenuconfig EXPERT 16576a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1658f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1659f505c553SJosh Triplett select DEBUG_KERNEL 16601da177e4SLinus Torvalds help 16611da177e4SLinus Torvalds This option allows certain base kernel options and settings 16621da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 16631da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 16641da177e4SLinus Torvalds Only use this if you really know what you are doing. 16651da177e4SLinus Torvalds 1666ae81f9e3SChuck Ebbertconfig UID16 16676a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 16682813893fSIulia Manda depends on HAVE_UID16 && MULTIUSER 1669ae81f9e3SChuck Ebbert default y 1670ae81f9e3SChuck Ebbert help 1671ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1672ae81f9e3SChuck Ebbert 16732813893fSIulia Mandaconfig MULTIUSER 16742813893fSIulia Manda bool "Multiple users, groups and capabilities support" if EXPERT 16752813893fSIulia Manda default y 16762813893fSIulia Manda help 16772813893fSIulia Manda This option enables support for non-root users, groups and 16782813893fSIulia Manda capabilities. 16792813893fSIulia Manda 16802813893fSIulia Manda If you say N here, all processes will run with UID 0, GID 0, and all 16812813893fSIulia Manda possible capabilities. Saying N here also compiles out support for 16822813893fSIulia Manda system calls related to UIDs, GIDs, and capabilities, such as setuid, 16832813893fSIulia Manda setgid, and capset. 16842813893fSIulia Manda 16852813893fSIulia Manda If unsure, say Y here. 16862813893fSIulia Manda 1687f6187769SFabian Frederickconfig SGETMASK_SYSCALL 1688f6187769SFabian Frederick bool "sgetmask/ssetmask syscalls support" if EXPERT 1689cd14b018SMasahiro Yamada default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1690a7f7f624SMasahiro Yamada help 1691f6187769SFabian Frederick sys_sgetmask and sys_ssetmask are obsolete system calls 1692f6187769SFabian Frederick no longer supported in libc but still enabled by default in some 1693f6187769SFabian Frederick architectures. 1694f6187769SFabian Frederick 1695f6187769SFabian Frederick If unsure, leave the default option here. 1696f6187769SFabian Frederick 1697d1b069f5SRandy Dunlapconfig FHANDLE 1698d1b069f5SRandy Dunlap bool "open by fhandle syscalls" if EXPERT 1699d1b069f5SRandy Dunlap select EXPORTFS 1700d1b069f5SRandy Dunlap default y 1701d1b069f5SRandy Dunlap help 1702d1b069f5SRandy Dunlap If you say Y here, a user level program will be able to map 1703d1b069f5SRandy Dunlap file names to handle and then later use the handle for 1704d1b069f5SRandy Dunlap different file system operations. This is useful in implementing 1705d1b069f5SRandy Dunlap userspace file servers, which now track files using handles instead 1706d1b069f5SRandy Dunlap of names. The handle would remain the same even if file names 1707d1b069f5SRandy Dunlap get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1708d1b069f5SRandy Dunlap syscalls. 1709d1b069f5SRandy Dunlap 1710baa73d9eSNicolas Pitreconfig POSIX_TIMERS 1711baa73d9eSNicolas Pitre bool "Posix Clocks & timers" if EXPERT 1712baa73d9eSNicolas Pitre default y 1713baa73d9eSNicolas Pitre help 1714baa73d9eSNicolas Pitre This includes native support for POSIX timers to the kernel. 1715baa73d9eSNicolas Pitre Some embedded systems have no use for them and therefore they 1716baa73d9eSNicolas Pitre can be configured out to reduce the size of the kernel image. 1717baa73d9eSNicolas Pitre 1718baa73d9eSNicolas Pitre When this option is disabled, the following syscalls won't be 1719baa73d9eSNicolas Pitre available: timer_create, timer_gettime: timer_getoverrun, 1720baa73d9eSNicolas Pitre timer_settime, timer_delete, clock_adjtime, getitimer, 1721baa73d9eSNicolas Pitre setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1722baa73d9eSNicolas Pitre clock_getres and clock_nanosleep syscalls will be limited to 1723baa73d9eSNicolas Pitre CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1724baa73d9eSNicolas Pitre 1725baa73d9eSNicolas Pitre If unsure say y. 1726baa73d9eSNicolas Pitre 1727d59745ceSMatt Mackallconfig PRINTK 1728d59745ceSMatt Mackall default y 17296a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 173074876a98SFrederic Weisbecker select IRQ_WORK 1731d59745ceSMatt Mackall help 1732d59745ceSMatt Mackall This option enables normal printk support. Removing it 1733d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1734d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1735d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1736d59745ceSMatt Mackall strongly discouraged. 1737d59745ceSMatt Mackall 17385ea2bcdfSThomas Weißschuhconfig PRINTK_RINGBUFFER_KUNIT_TEST 17395ea2bcdfSThomas Weißschuh tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 17405ea2bcdfSThomas Weißschuh depends on PRINTK && KUNIT 17415ea2bcdfSThomas Weißschuh default KUNIT_ALL_TESTS 17425ea2bcdfSThomas Weißschuh help 17435ea2bcdfSThomas Weißschuh This builds the printk ringbuffer KUnit test suite. 17445ea2bcdfSThomas Weißschuh 17455ea2bcdfSThomas Weißschuh For more information on KUnit and unit tests in general, please refer 17465ea2bcdfSThomas Weißschuh to the KUnit documentation. 17475ea2bcdfSThomas Weißschuh 17485ea2bcdfSThomas Weißschuh If unsure, say N. 17495ea2bcdfSThomas Weißschuh 1750c8538a7aSMatt Mackallconfig BUG 17516a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1752c8538a7aSMatt Mackall default y 1753c8538a7aSMatt Mackall help 1754c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1755c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1756c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1757c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1758c8538a7aSMatt Mackall Just say Y. 1759c8538a7aSMatt Mackall 1760708e9a79SMatt Mackallconfig ELF_CORE 1761046d662fSAlex Kelly depends on COREDUMP 1762708e9a79SMatt Mackall default y 17636a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1764708e9a79SMatt Mackall help 1765708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1766708e9a79SMatt Mackall 17678761f1abSRalf Baechle 1768e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 17696a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 17708761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 177115f304b6SRalf Baechle select I8253_LOCK 1772e5e1d3cbSStas Sergeev default y 1773e5e1d3cbSStas Sergeev help 1774e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1775e5e1d3cbSStas Sergeev support, saving some memory. 1776e5e1d3cbSStas Sergeev 177727021649SYoann Congalconfig BASE_SMALL 177827021649SYoann Congal bool "Enable smaller-sized data structures for core" if EXPERT 17791da177e4SLinus Torvalds help 178027021649SYoann Congal Enabling this option reduces the size of miscellaneous core 17811da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 17821da177e4SLinus Torvalds but may reduce performance. 17831da177e4SLinus Torvalds 17841da177e4SLinus Torvaldsconfig FUTEX 17856a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 17863f2bedabSArnd Bergmann depends on !(SPARC32 && SMP) 17871da177e4SLinus Torvalds default y 1788bc2eecd7SNicolas Pitre imply RT_MUTEXES 17891da177e4SLinus Torvalds help 17901da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 17911da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 17921da177e4SLinus Torvalds run glibc-based applications correctly. 17931da177e4SLinus Torvalds 1794bc2eecd7SNicolas Pitreconfig FUTEX_PI 1795bc2eecd7SNicolas Pitre bool 1796bc2eecd7SNicolas Pitre depends on FUTEX && RT_MUTEXES 1797bc2eecd7SNicolas Pitre default y 1798bc2eecd7SNicolas Pitre 179980367ad0SSebastian Andrzej Siewiorconfig FUTEX_PRIVATE_HASH 180080367ad0SSebastian Andrzej Siewior bool 180180367ad0SSebastian Andrzej Siewior depends on FUTEX && !BASE_SMALL && MMU 180280367ad0SSebastian Andrzej Siewior default y 180380367ad0SSebastian Andrzej Siewior 1804c042c505SPeter Zijlstraconfig FUTEX_MPOL 1805c042c505SPeter Zijlstra bool 1806c042c505SPeter Zijlstra depends on FUTEX && NUMA 1807c042c505SPeter Zijlstra default y 1808c042c505SPeter Zijlstra 18091da177e4SLinus Torvaldsconfig EPOLL 18106a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 18111da177e4SLinus Torvalds default y 18121da177e4SLinus Torvalds help 18131da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18141da177e4SLinus Torvalds support for epoll family of system calls. 18151da177e4SLinus Torvalds 1816fba2afaaSDavide Libenziconfig SIGNALFD 18176a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1818fba2afaaSDavide Libenzi default y 1819fba2afaaSDavide Libenzi help 1820fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1821fba2afaaSDavide Libenzi on a file descriptor. 1822fba2afaaSDavide Libenzi 1823fba2afaaSDavide Libenzi If unsure, say Y. 1824fba2afaaSDavide Libenzi 1825b215e283SDavide Libenziconfig TIMERFD 18266a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1827b215e283SDavide Libenzi default y 1828b215e283SDavide Libenzi help 1829b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1830b215e283SDavide Libenzi events on a file descriptor. 1831b215e283SDavide Libenzi 1832b215e283SDavide Libenzi If unsure, say Y. 1833b215e283SDavide Libenzi 1834e1ad7468SDavide Libenziconfig EVENTFD 18356a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1836e1ad7468SDavide Libenzi default y 1837e1ad7468SDavide Libenzi help 1838e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1839e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1840e1ad7468SDavide Libenzi 1841e1ad7468SDavide Libenzi If unsure, say Y. 1842e1ad7468SDavide Libenzi 18431da177e4SLinus Torvaldsconfig SHMEM 18446a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 18451da177e4SLinus Torvalds default y 18461da177e4SLinus Torvalds depends on MMU 18471da177e4SLinus Torvalds help 18481da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 18491da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 18501da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 18511da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 18521da177e4SLinus Torvalds which may be appropriate on small systems without swap. 18531da177e4SLinus Torvalds 1854ebf3f09cSThomas Petazzoniconfig AIO 18556a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1856ebf3f09cSThomas Petazzoni default y 1857ebf3f09cSThomas Petazzoni help 1858ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1859ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1860ebf3f09cSThomas Petazzoni this option saves about 7k. 1861ebf3f09cSThomas Petazzoni 18622b188cc1SJens Axboeconfig IO_URING 18632b188cc1SJens Axboe bool "Enable IO uring support" if EXPERT 1864561fb04aSJens Axboe select IO_WQ 18652b188cc1SJens Axboe default y 18662b188cc1SJens Axboe help 18672b188cc1SJens Axboe This option enables support for the io_uring interface, enabling 18682b188cc1SJens Axboe applications to submit and complete IO through submission and 18692b188cc1SJens Axboe completion rings that are shared between the kernel and application. 18702b188cc1SJens Axboe 18711802656eSJens Axboeconfig GCOV_PROFILE_URING 18721802656eSJens Axboe bool "Enable GCOV profiling on the io_uring subsystem" 1873d1fbe1ebSRandy Dunlap depends on IO_URING && GCOV_KERNEL 18741802656eSJens Axboe help 18751802656eSJens Axboe Enable GCOV profiling on the io_uring subsystem, to facilitate 18761802656eSJens Axboe code coverage testing. 18771802656eSJens Axboe 18781802656eSJens Axboe If unsure, say N. 18791802656eSJens Axboe 18801802656eSJens Axboe Note that this will have a negative impact on the performance of 18811802656eSJens Axboe the io_uring subsystem, hence this should only be enabled for 18821802656eSJens Axboe specific test purposes. 18831802656eSJens Axboe 18843a0ae385SPavel Begunkovconfig IO_URING_MOCK_FILE 18853a0ae385SPavel Begunkov tristate "Enable io_uring mock files (Experimental)" if EXPERT 18863a0ae385SPavel Begunkov default n 18873a0ae385SPavel Begunkov depends on IO_URING 18883a0ae385SPavel Begunkov help 18893a0ae385SPavel Begunkov Enable mock files for io_uring subststem testing. The ABI might 18903a0ae385SPavel Begunkov still change, so it's still experimental and should only be enabled 18913a0ae385SPavel Begunkov for specific test purposes. 18923a0ae385SPavel Begunkov 18933a0ae385SPavel Begunkov If unsure, say N. 18943a0ae385SPavel Begunkov 1895d3ac21caSJosh Triplettconfig ADVISE_SYSCALLS 1896d3ac21caSJosh Triplett bool "Enable madvise/fadvise syscalls" if EXPERT 1897d3ac21caSJosh Triplett default y 1898d3ac21caSJosh Triplett help 1899d3ac21caSJosh Triplett This option enables the madvise and fadvise syscalls, used by 1900d3ac21caSJosh Triplett applications to advise the kernel about their future memory or file 1901d3ac21caSJosh Triplett usage, improving performance. If building an embedded system where no 1902d3ac21caSJosh Triplett applications use these syscalls, you can disable this option to save 1903d3ac21caSJosh Triplett space. 1904d3ac21caSJosh Triplett 19055b25b13aSMathieu Desnoyersconfig MEMBARRIER 19065b25b13aSMathieu Desnoyers bool "Enable membarrier() system call" if EXPERT 19075b25b13aSMathieu Desnoyers default y 19085b25b13aSMathieu Desnoyers help 19095b25b13aSMathieu Desnoyers Enable the membarrier() system call that allows issuing memory 19105b25b13aSMathieu Desnoyers barriers across all running threads, which can be used to distribute 19115b25b13aSMathieu Desnoyers the cost of user-space memory barriers asymmetrically by transforming 19125b25b13aSMathieu Desnoyers pairs of memory barriers into pairs consisting of membarrier() and a 19135b25b13aSMathieu Desnoyers compiler barrier. 19145b25b13aSMathieu Desnoyers 19155b25b13aSMathieu Desnoyers If unsure, say Y. 19165b25b13aSMathieu Desnoyers 1917a751ea34SRandy Dunlapconfig KCMP 1918a751ea34SRandy Dunlap bool "Enable kcmp() system call" if EXPERT 1919a751ea34SRandy Dunlap help 1920a751ea34SRandy Dunlap Enable the kernel resource comparison system call. It provides 1921a751ea34SRandy Dunlap user-space with the ability to compare two processes to see if they 1922a751ea34SRandy Dunlap share a common resource, such as a file descriptor or even virtual 1923a751ea34SRandy Dunlap memory space. 1924a751ea34SRandy Dunlap 1925a751ea34SRandy Dunlap If unsure, say N. 1926a751ea34SRandy Dunlap 1927a751ea34SRandy Dunlapconfig RSEQ 1928a751ea34SRandy Dunlap bool "Enable rseq() system call" if EXPERT 1929a751ea34SRandy Dunlap default y 1930a751ea34SRandy Dunlap depends on HAVE_RSEQ 1931a751ea34SRandy Dunlap select MEMBARRIER 1932a751ea34SRandy Dunlap help 1933a751ea34SRandy Dunlap Enable the restartable sequences system call. It provides a 1934a751ea34SRandy Dunlap user-space cache for the current CPU number value, which 1935a751ea34SRandy Dunlap speeds up getting the current CPU number from user-space, 1936a751ea34SRandy Dunlap as well as an ABI to speed up user-space operations on 1937a751ea34SRandy Dunlap per-CPU data. 1938a751ea34SRandy Dunlap 1939a751ea34SRandy Dunlap If unsure, say Y. 1940a751ea34SRandy Dunlap 194154129104SThomas Gleixnerconfig RSEQ_STATS 194254129104SThomas Gleixner default n 194354129104SThomas Gleixner bool "Enable lightweight statistics of restartable sequences" if EXPERT 194454129104SThomas Gleixner depends on RSEQ && DEBUG_FS 194554129104SThomas Gleixner help 194654129104SThomas Gleixner Enable lightweight counters which expose information about the 194754129104SThomas Gleixner frequency of RSEQ operations via debugfs. Mostly interesting for 194854129104SThomas Gleixner kernel debugging or performance analysis. While lightweight it's 194954129104SThomas Gleixner still adding code into the user/kernel mode transitions. 195054129104SThomas Gleixner 195154129104SThomas Gleixner If unsure, say N. 195254129104SThomas Gleixner 19539c37cb6eSThomas Gleixnerconfig RSEQ_DEBUG_DEFAULT_ENABLE 19549c37cb6eSThomas Gleixner default n 19559c37cb6eSThomas Gleixner bool "Enable restartable sequences debug mode by default" if EXPERT 19569c37cb6eSThomas Gleixner depends on RSEQ 19579c37cb6eSThomas Gleixner help 19589c37cb6eSThomas Gleixner This enables the static branch for debug mode of restartable 19599c37cb6eSThomas Gleixner sequences. 19609c37cb6eSThomas Gleixner 19619c37cb6eSThomas Gleixner This also can be controlled on the kernel command line via the 19629c37cb6eSThomas Gleixner command line parameter "rseq_debug=0/1" and through debugfs. 19639c37cb6eSThomas Gleixner 19649c37cb6eSThomas Gleixner If unsure, say N. 19659c37cb6eSThomas Gleixner 1966a751ea34SRandy Dunlapconfig DEBUG_RSEQ 1967a751ea34SRandy Dunlap default n 1968a751ea34SRandy Dunlap bool "Enable debugging of rseq() system call" if EXPERT 19693db6b38dSThomas Gleixner depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 19709c37cb6eSThomas Gleixner select RSEQ_DEBUG_DEFAULT_ENABLE 1971a751ea34SRandy Dunlap help 1972a751ea34SRandy Dunlap Enable extra debugging checks for the rseq system call. 1973a751ea34SRandy Dunlap 1974a751ea34SRandy Dunlap If unsure, say N. 1975a751ea34SRandy Dunlap 1976a751ea34SRandy Dunlapconfig CACHESTAT_SYSCALL 1977a751ea34SRandy Dunlap bool "Enable cachestat() system call" if EXPERT 1978a751ea34SRandy Dunlap default y 1979a751ea34SRandy Dunlap help 1980a751ea34SRandy Dunlap Enable the cachestat system call, which queries the page cache 1981a751ea34SRandy Dunlap statistics of a file (number of cached pages, dirty pages, 1982a751ea34SRandy Dunlap pages marked for writeback, (recently) evicted pages). 1983a751ea34SRandy Dunlap 1984a751ea34SRandy Dunlap If unsure say Y here. 1985a751ea34SRandy Dunlap 1986d1b069f5SRandy Dunlapconfig KALLSYMS 1987d1b069f5SRandy Dunlap bool "Load all symbols for debugging/ksymoops" if EXPERT 1988d1b069f5SRandy Dunlap default y 1989d1b069f5SRandy Dunlap help 1990d1b069f5SRandy Dunlap Say Y here to let the kernel print out symbolic crash information and 1991d1b069f5SRandy Dunlap symbolic stack backtraces. This increases the size of the kernel 1992d1b069f5SRandy Dunlap somewhat, as all symbols have to be loaded into the kernel image. 1993d1b069f5SRandy Dunlap 199430f3bb09SZhen Leiconfig KALLSYMS_SELFTEST 199530f3bb09SZhen Lei bool "Test the basic functions and performance of kallsyms" 199630f3bb09SZhen Lei depends on KALLSYMS 199730f3bb09SZhen Lei default n 199830f3bb09SZhen Lei help 199930f3bb09SZhen Lei Test the basic functions and performance of some interfaces, such as 200030f3bb09SZhen Lei kallsyms_lookup_name. It also calculates the compression rate of the 200130f3bb09SZhen Lei kallsyms compression algorithm for the current symbol set. 200230f3bb09SZhen Lei 200330f3bb09SZhen Lei Start self-test automatically after system startup. Suggest executing 200430f3bb09SZhen Lei "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 200530f3bb09SZhen Lei displayed in the last line, indicating that the test is complete. 200630f3bb09SZhen Lei 2007d1b069f5SRandy Dunlapconfig KALLSYMS_ALL 2008d1b069f5SRandy Dunlap bool "Include all symbols in kallsyms" 2009d1b069f5SRandy Dunlap depends on DEBUG_KERNEL && KALLSYMS 2010d1b069f5SRandy Dunlap help 2011d1b069f5SRandy Dunlap Normally kallsyms only contains the symbols of functions for nicer 2012d1b069f5SRandy Dunlap OOPS messages and backtraces (i.e., symbols from the text and inittext 2013bdf0fe33SBaruch Siach sections). This is sufficient for most cases. And only if you want to 2014bdf0fe33SBaruch Siach enable kernel live patching, or other less common use cases (e.g., 2015bdf0fe33SBaruch Siach when a debugger is used) all symbols are required (i.e., names of 2016bdf0fe33SBaruch Siach variables from the data sections, etc). 2017d1b069f5SRandy Dunlap 2018d1b069f5SRandy Dunlap This option makes sure that all symbols are loaded into the kernel 2019d1b069f5SRandy Dunlap image (i.e., symbols from all sections) in cost of increased kernel 2020d1b069f5SRandy Dunlap size (depending on the kernel configuration, it may be 300KiB or 2021d1b069f5SRandy Dunlap something like this). 2022d1b069f5SRandy Dunlap 2023bdf0fe33SBaruch Siach Say N unless you really need all symbols, or kernel live patching. 2024d1b069f5SRandy Dunlap 2025d1b069f5SRandy Dunlap# end of the "standard kernel features (expert users)" menu 2026d1b069f5SRandy Dunlap 20273ccfebedSMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_CALLBACKS 20283ccfebedSMathieu Desnoyers bool 20293ccfebedSMathieu Desnoyers 203070216e18SMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_SYNC_CORE 203170216e18SMathieu Desnoyers bool 203270216e18SMathieu Desnoyers 20335796d396SJeff Xuconfig ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 20345796d396SJeff Xu bool 20355796d396SJeff Xu help 20365796d396SJeff Xu Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 20375796d396SJeff Xu 20385796d396SJeff Xu A 64-bit kernel is required for the memory sealing feature. 20395796d396SJeff Xu No specific hardware features from the CPU are needed. 20405796d396SJeff Xu 20415796d396SJeff Xu To enable this feature, the architecture needs to update their 20425796d396SJeff Xu special mappings calls to include the sealing flag and confirm 20435796d396SJeff Xu that it doesn't unmap/remap system mappings during the life 20445796d396SJeff Xu time of the process. The existence of this flag for an architecture 20455796d396SJeff Xu implies that it does not require the remapping of the system 20465796d396SJeff Xu mappings during process lifetime, so sealing these mappings is safe 20475796d396SJeff Xu from a kernel perspective. 20485796d396SJeff Xu 20495796d396SJeff Xu After the architecture enables this, a distribution can set 20505796d396SJeff Xu CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 20515796d396SJeff Xu 20525796d396SJeff Xu For complete descriptions of memory sealing, please see 20535796d396SJeff Xu Documentation/userspace-api/mseal.rst 20545796d396SJeff Xu 2055cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 20560793a61dSThomas Gleixner bool 2057018df72dSMike Frysinger help 2058018df72dSMike Frysinger See tools/perf/design.txt for details. 20590793a61dSThomas Gleixner 20602aef6f30SSean Christophersonconfig GUEST_PERF_EVENTS 20612aef6f30SSean Christopherson bool 20622aef6f30SSean Christopherson depends on HAVE_PERF_EVENTS 20632aef6f30SSean Christopherson 2064906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 2065906010b2SPeter Zijlstra bool 2066906010b2SPeter Zijlstra help 2067906010b2SPeter Zijlstra See tools/perf/design.txt for details 2068906010b2SPeter Zijlstra 206957c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 20700793a61dSThomas Gleixner 2071cdd6c482SIngo Molnarconfig PERF_EVENTS 207257c0c15bSIngo Molnar bool "Kernel performance events and counters" 2073392d65a9SRobert Richter default y if PROFILING 2074cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 2075e360adbeSPeter Zijlstra select IRQ_WORK 20760793a61dSThomas Gleixner help 207757c0c15bSIngo Molnar Enable kernel support for various performance events provided 207857c0c15bSIngo Molnar by software and hardware. 20790793a61dSThomas Gleixner 2080dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 208157c0c15bSIngo Molnar use of generic tracepoints. 208257c0c15bSIngo Molnar 208357c0c15bSIngo Molnar Most modern CPUs support performance events via performance 208457c0c15bSIngo Molnar counter registers. These registers count the number of certain 20850793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 20860793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 20870793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 20880793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 20890793a61dSThomas Gleixner used to profile the code that runs on that CPU. 20900793a61dSThomas Gleixner 209157c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 2092dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 209357c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 20940793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 20950793a61dSThomas Gleixner capabilities on top of those. 20960793a61dSThomas Gleixner 20970793a61dSThomas Gleixner Say Y if unsure. 20980793a61dSThomas Gleixner 2099906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 2100906010b2SPeter Zijlstra default n 2101906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 2102cb307113SMichael Ellerman depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2103906010b2SPeter Zijlstra select PERF_USE_VMALLOC 2104906010b2SPeter Zijlstra help 2105906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 2106906010b2SPeter Zijlstra 2107906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 2108906010b2SPeter Zijlstra that don't require it. 2109906010b2SPeter Zijlstra 2110906010b2SPeter Zijlstra Say N if unsure. 2111906010b2SPeter Zijlstra 21120793a61dSThomas Gleixnerendmenu 21130793a61dSThomas Gleixner 2114091f6e26SDavid Howellsconfig SYSTEM_DATA_VERIFICATION 2115091f6e26SDavid Howells def_bool n 2116091f6e26SDavid Howells select SYSTEM_TRUSTED_KEYRING 2117091f6e26SDavid Howells select KEYS 2118091f6e26SDavid Howells select CRYPTO 2119d43de6c7SDavid Howells select CRYPTO_RSA 2120091f6e26SDavid Howells select ASYMMETRIC_KEY_TYPE 2121091f6e26SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2122091f6e26SDavid Howells select ASN1 2123091f6e26SDavid Howells select OID_REGISTRY 2124091f6e26SDavid Howells select X509_CERTIFICATE_PARSER 2125091f6e26SDavid Howells select PKCS7_MESSAGE_PARSER 212682c04ff8SPeter Foley help 2127091f6e26SDavid Howells Provide PKCS#7 message verification using the contents of the system 2128091f6e26SDavid Howells trusted keyring to provide public keys. This then can be used for 2129091f6e26SDavid Howells module verification, kexec image verification and firmware blob 2130091f6e26SDavid Howells verification. 213182c04ff8SPeter Foley 2132125e5645SMathieu Desnoyersconfig PROFILING 2133b309a294SRobert Richter bool "Profiling support" 2134125e5645SMathieu Desnoyers help 2135125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 2136f8408264SViresh Kumar by profilers. 2137125e5645SMathieu Desnoyers 21382f7ab126SMiguel Ojedaconfig RUST 21392f7ab126SMiguel Ojeda bool "Rust support" 21402f7ab126SMiguel Ojeda depends on HAVE_RUST 21412f7ab126SMiguel Ojeda depends on RUST_IS_AVAILABLE 2142ac61506bSSami Tolvanen select EXTENDED_MODVERSIONS if MODVERSIONS 2143ac61506bSSami Tolvanen depends on !MODVERSIONS || GENDWARFKSYMS 2144f1385dc6SNeal Gompa depends on !GCC_PLUGIN_RANDSTRUCT 21452f7ab126SMiguel Ojeda depends on !RANDSTRUCT 21465daa0c35SMatthew Maurer depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 214723ef9d43SKees Cook depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 214823ef9d43SKees Cook select CFI_ICALL_NORMALIZE_INTEGERS if CFI 2149af6017b6SMiguel Ojeda depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2150f64e2f3aSMatthew Maurer depends on !KASAN_SW_TAGS 215193e34a0bSAlice Ryhl depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 21522f7ab126SMiguel Ojeda help 21532f7ab126SMiguel Ojeda Enables Rust support in the kernel. 21542f7ab126SMiguel Ojeda 21552f7ab126SMiguel Ojeda This allows other Rust-related options, like drivers written in Rust, 21562f7ab126SMiguel Ojeda to be selected. 21572f7ab126SMiguel Ojeda 21582f7ab126SMiguel Ojeda It is also required to be able to load external kernel modules 21592f7ab126SMiguel Ojeda written in Rust. 21602f7ab126SMiguel Ojeda 21612f7ab126SMiguel Ojeda See Documentation/rust/ for more information. 21622f7ab126SMiguel Ojeda 21632f7ab126SMiguel Ojeda If unsure, say N. 21642f7ab126SMiguel Ojeda 21652f7ab126SMiguel Ojedaconfig RUSTC_VERSION_TEXT 21662f7ab126SMiguel Ojeda string 21672f7ab126SMiguel Ojeda depends on RUST 21685134a335SMiguel Ojeda default "$(RUSTC_VERSION_TEXT)" 21695134a335SMiguel Ojeda help 21705134a335SMiguel Ojeda See `CC_VERSION_TEXT`. 21712f7ab126SMiguel Ojeda 21722f7ab126SMiguel Ojedaconfig BINDGEN_VERSION_TEXT 21732f7ab126SMiguel Ojeda string 21742f7ab126SMiguel Ojeda depends on RUST 21759e98db17SMiguel Ojeda # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2176c23d1f7eSMiguel Ojeda # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2177c23d1f7eSMiguel Ojeda # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2178c23d1f7eSMiguel Ojeda # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2179c23d1f7eSMiguel Ojeda # both fixed the issue). 2180aacf93e8SMasahiro Yamada default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 21812f7ab126SMiguel Ojeda 21825f87f112SIngo Molnar# 21835f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 21845f87f112SIngo Molnar# dynamically changed for a probe function. 21855f87f112SIngo Molnar# 218697e1c18eSMathieu Desnoyersconfig TRACEPOINTS 21875f87f112SIngo Molnar bool 2188a363d27cSMathieu Desnoyers select TASKS_TRACE_RCU 218997e1c18eSMathieu Desnoyers 219089cde455SEric DeVoldersource "kernel/Kconfig.kexec" 219189cde455SEric DeVolder 2192*48a1b232SPasha Tatashinsource "kernel/liveupdate/Kconfig" 2193*48a1b232SPasha Tatashin 21941da177e4SLinus Torvaldsendmenu # General setup 21951da177e4SLinus Torvalds 21961572497cSChristoph Hellwigsource "arch/Kconfig" 21971572497cSChristoph Hellwig 2198ae81f9e3SChuck Ebbertconfig RT_MUTEXES 21996341e62bSChristoph Jaeger bool 22001c6f9ec0SSebastian Andrzej Siewior default y if PREEMPT_RT 2201ae81f9e3SChuck Ebbert 2202c8424e77SThiago Jung Bauermannconfig MODULE_SIG_FORMAT 2203c8424e77SThiago Jung Bauermann def_bool n 2204c8424e77SThiago Jung Bauermann select SYSTEM_DATA_VERIFICATION 2205c8424e77SThiago Jung Bauermann 220673b4fc92SChristophe Leroysource "kernel/module/Kconfig" 22076c9692e2SPeter Zijlstra 220898a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 220998a79d6aSRusty Russell bool 221098a79d6aSRusty Russell help 22115f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 22125f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 221398a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 221498a79d6aSRusty Russell it was better to provide this option than to break all the archs 2215692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 221698a79d6aSRusty Russell 22173a65dfe8SJens Axboesource "block/Kconfig" 2218e98c3202SAvi Kivity 2219e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 2220e98c3202SAvi Kivity bool 2221e260be67SPaul E. McKenney 222216295becSSteffen Klassertconfig PADATA 222316295becSSteffen Klassert depends on SMP 222416295becSSteffen Klassert bool 222516295becSSteffen Klassert 22264520c6a4SDavid Howellsconfig ASN1 22274520c6a4SDavid Howells tristate 22284520c6a4SDavid Howells help 22294520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 22304520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 22314520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 22324520c6a4SDavid Howells functions to call on what tags. 22334520c6a4SDavid Howells 22346beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 2235e61938a9SMathieu Desnoyers 22360ebeea8cSDaniel Borkmannconfig ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 22370ebeea8cSDaniel Borkmann bool 22380ebeea8cSDaniel Borkmann 22394ff4c745SAndrea Parriconfig ARCH_HAS_PREPARE_SYNC_CORE_CMD 22404ff4c745SAndrea Parri bool 22414ff4c745SAndrea Parri 2242e61938a9SMathieu Desnoyersconfig ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2243e61938a9SMathieu Desnoyers bool 22441bd21c6cSDominik Brodowski 22451bd21c6cSDominik Brodowski# It may be useful for an architecture to override the definitions of the 22467303e30eSDominik Brodowski# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 22477303e30eSDominik Brodowski# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 22487303e30eSDominik Brodowski# different calling convention for syscalls. They can also override the 22497303e30eSDominik Brodowski# macros for not-implemented syscalls in kernel/sys_ni.c and 22507303e30eSDominik Brodowski# kernel/time/posix-stubs.c. All these overrides need to be available in 22517303e30eSDominik Brodowski# <asm/syscall_wrapper.h>. 22521bd21c6cSDominik Brodowskiconfig ARCH_HAS_SYSCALL_WRAPPER 22531bd21c6cSDominik Brodowski def_bool n 2254