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 85e90f97ceSGary Guoconfig RUSTC_LLVM_MAJOR_VERSION 86e90f97ceSGary Guo int 87e90f97ceSGary Guo default $(shell,expr $(rustc-llvm-version) / 10000) 88e90f97ceSGary Guo 89e90f97ceSGary Guoconfig RUSTC_CLANG_LLVM_COMPATIBLE 90e90f97ceSGary Guo bool 91e90f97ceSGary Guo default y if CC_IS_CLANG && RUSTC_LLVM_MAJOR_VERSION = $(shell,expr $(cc-version) / 10000) 92e90f97ceSGary Guo help 93e90f97ceSGary Guo This indicates whether Rust and Clang use LLVM of the same major 94e90f97ceSGary Guo version. 95e90f97ceSGary Guo 96e90f97ceSGary Guo Operations involving handling LLVM IR or bitcode (e.g. cross-language 97e90f97ceSGary Guo LTO) require the same LLVM major version to work properly. For best 98e90f97ceSGary Guo compatibility it is recommended that the exact same LLVM is used. 99e90f97ceSGary Guo 100deab487eSThomas Weißschuhconfig ARCH_HAS_CC_CAN_LINK 101deab487eSThomas Weißschuh bool 102deab487eSThomas Weißschuh 1031a927fd3SMasahiro Yamadaconfig CC_CAN_LINK 1049371f86eSMasahiro Yamada bool 105deab487eSThomas Weißschuh default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK 10680623f2cSThomas Weißschuh default $(cc_can_link_user,$(m64-flag)) if 64BIT 10780623f2cSThomas Weißschuh default $(cc_can_link_user,$(m32-flag)) 1081a927fd3SMasahiro Yamada 109f2f6a8e8SMark Rutland# Fixed in GCC 14, 13.3, 12.4 and 11.5 110f2f6a8e8SMark Rutland# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 111f2f6a8e8SMark Rutlandconfig GCC_ASM_GOTO_OUTPUT_BROKEN 112f2f6a8e8SMark Rutland bool 113f2f6a8e8SMark Rutland depends on CC_IS_GCC 114f2f6a8e8SMark Rutland default y if GCC_VERSION < 110500 115f2f6a8e8SMark Rutland default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 116f2f6a8e8SMark Rutland default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 117f2f6a8e8SMark Rutland 118587f1701SNick Desaulniersconfig CC_HAS_ASM_GOTO_OUTPUT 119f2f6a8e8SMark Rutland def_bool y 120f2f6a8e8SMark Rutland depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 121f2f6a8e8SMark 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) 122587f1701SNick Desaulniers 1231aa0e8b1SSean Christophersonconfig CC_HAS_ASM_GOTO_TIED_OUTPUT 1241aa0e8b1SSean Christopherson depends on CC_HAS_ASM_GOTO_OUTPUT 1251aa0e8b1SSean Christopherson # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 126534bd703SAlexandre 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) 1271aa0e8b1SSean Christopherson 1285cf896fbSPeter Collingbourneconfig TOOLS_SUPPORT_RELR 1292d122942SWill Deacon def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 1305cf896fbSPeter Collingbourne 131eb111869SRasmus Villemoesconfig CC_HAS_ASM_INLINE 132eb111869SRasmus Villemoes def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 133eb111869SRasmus Villemoes 134f72e2cffSHeiko Carstensconfig CC_HAS_ASSUME 135f72e2cffSHeiko Carstens bool 136f72e2cffSHeiko Carstens # clang needs to be at least 19.1.0 since the meaning of the assume 137f72e2cffSHeiko Carstens # attribute changed: 138f72e2cffSHeiko Carstens # https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17 139f72e2cffSHeiko Carstens default y if CC_IS_CLANG && CLANG_VERSION >= 190100 140f72e2cffSHeiko Carstens # supported since gcc 13.1.0 141f72e2cffSHeiko Carstens # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654 142f72e2cffSHeiko Carstens default y if CC_IS_GCC && GCC_VERSION >= 130100 143f72e2cffSHeiko Carstens 14451c2ee6dSNick Desaulniersconfig CC_HAS_NO_PROFILE_FN_ATTR 14551c2ee6dSNick Desaulniers def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 14651c2ee6dSNick Desaulniers 147f06e108aSJan Hendrik Farrconfig CC_HAS_COUNTED_BY 1485106c650SJan Hendrik Farr bool 14986a9b125SNathan Chancellor # clang needs to be at least 20.1.0 to avoid potential crashes 15086a9b125SNathan Chancellor # when building structures that contain __counted_by 15186a9b125SNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/2114 15286a9b125SNathan Chancellor # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 15386a9b125SNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION >= 200100 1545106c650SJan Hendrik Farr # supported since gcc 15.1.0 1555106c650SJan Hendrik Farr # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 1565106c650SJan Hendrik Farr default y if CC_IS_GCC && GCC_VERSION >= 150100 157f06e108aSJan Hendrik Farr 158150a04d8SBill Wendlingconfig CC_HAS_COUNTED_BY_PTR 159150a04d8SBill Wendling bool 160150a04d8SBill Wendling # supported since clang 22 1617a618ca9SNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION >= 220100 162150a04d8SBill Wendling # supported since gcc 16.0.0 163150a04d8SBill Wendling default y if CC_IS_GCC && GCC_VERSION >= 160000 164150a04d8SBill Wendling 165d39a1d74SKees Cookconfig CC_HAS_BROKEN_COUNTED_BY_REF 166d39a1d74SKees Cook bool 167d39a1d74SKees Cook # https://github.com/llvm/llvm-project/issues/182575 168f709859fSNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION < 220100 169d39a1d74SKees Cook 170feb662d9SMarco Elverconfig CC_HAS_ALLOC_TOKEN 171feb662d9SMarco Elver def_bool $(cc-option,-falloc-token-max=123) 172feb662d9SMarco Elver 173b688f369SKees Cookconfig CC_HAS_MULTIDIMENSIONAL_NONSTRING 174b688f369SKees Cook def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 175b688f369SKees Cook 176e7607f7dSNathan Chancellorconfig LD_CAN_USE_KEEP_IN_OVERLAY 177e7607f7dSNathan Chancellor # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 178e7607f7dSNathan Chancellor # https://github.com/llvm/llvm-project/pull/130661 179e7607f7dSNathan Chancellor def_bool LD_IS_BFD || LLD_VERSION >= 210000 180e7607f7dSNathan Chancellor 18136174d16SMiguel Ojedaconfig RUSTC_HAS_SPAN_FILE 18236174d16SMiguel Ojeda def_bool RUSTC_VERSION >= 108800 18336174d16SMiguel Ojeda 1847129ea6eSMiguel Ojedaconfig RUSTC_HAS_UNNECESSARY_TRANSMUTES 1857129ea6eSMiguel Ojeda def_bool RUSTC_VERSION >= 108800 1867129ea6eSMiguel Ojeda 1870aa2b78cSBoqun Fengconfig RUSTC_HAS_FILE_WITH_NUL 1880aa2b78cSBoqun Feng def_bool RUSTC_VERSION >= 108900 1890aa2b78cSBoqun Feng 190c09461a0SAlice Ryhlconfig RUSTC_HAS_FILE_AS_C_STR 191c09461a0SAlice Ryhl def_bool RUSTC_VERSION >= 109100 192c09461a0SAlice Ryhl 193608045a9SMiguel Ojedaconfig RUSTC_HAS_SUSPICIOUS_RUNTIME_SYMBOL_DEFINITIONS 194608045a9SMiguel Ojeda def_bool RUSTC_VERSION >= 109800 195608045a9SMiguel Ojeda 196613fe169SNathan Chancellorconfig PAHOLE_VERSION 197613fe169SNathan Chancellor int 19890e5b38aSIhor Solodrai default "$(PAHOLE_VERSION)" 199613fe169SNathan Chancellor 200b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 201b99b87f7SPeter Oberparleiter bool 202b99b87f7SPeter Oberparleiter 203e360adbeSPeter Zijlstraconfig IRQ_WORK 204fd0a68a2STejun Heo def_bool y if SMP 205e360adbeSPeter Zijlstra 20610916706SShile Zhangconfig BUILDTIME_TABLE_SORT 2071dbdc6f1SDavid Daney bool 2081dbdc6f1SDavid Daney 209c65eacbeSAndy Lutomirskiconfig THREAD_INFO_IN_TASK 210c65eacbeSAndy Lutomirski bool 211c65eacbeSAndy Lutomirski help 212c65eacbeSAndy Lutomirski Select this to move thread_info off the stack into task_struct. To 213c65eacbeSAndy Lutomirski make this work, an arch will need to remove all thread_info fields 214c65eacbeSAndy Lutomirski except flags and fix any runtime bugs. 215c65eacbeSAndy Lutomirski 216c6c314a6SAndy Lutomirski One subtle change that will be needed is to use try_get_task_stack() 217c6c314a6SAndy Lutomirski and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 218c6c314a6SAndy Lutomirski 219ff0cfc66SAl Boldimenu "General setup" 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvaldsconfig BROKEN 2221da177e4SLinus Torvalds bool 223fefbeed8SAndrew Morton help 224fefbeed8SAndrew Morton This option allows you to choose whether you want to try to 225fefbeed8SAndrew Morton compile (and fix) old drivers that haven't been updated to 226fefbeed8SAndrew Morton new infrastructure. 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 2291da177e4SLinus Torvalds bool 2301da177e4SLinus Torvalds depends on BROKEN || !SMP 2311da177e4SLinus Torvalds default y 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 2341da177e4SLinus Torvalds int 235dd673bcaSAdrian Bunk default 32 if !UML 236dd673bcaSAdrian Bunk default 128 if UML 2371da177e4SLinus Torvalds help 23834ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 23934ad92c2SRandy Dunlap variables passed to init from the kernel command line. 2401da177e4SLinus Torvalds 2414bb16672SJiri Slabyconfig COMPILE_TEST 2424bb16672SJiri Slaby bool "Compile also drivers which will not load" 243ea29b20aSMasahiro Yamada depends on HAS_IOMEM 2444bb16672SJiri Slaby help 2454bb16672SJiri Slaby Some drivers can be compiled on a different platform than they are 2464bb16672SJiri Slaby intended to be run on. Despite they cannot be loaded there (or even 2474bb16672SJiri Slaby when they load they cannot be used due to missing HW support), 2484bb16672SJiri Slaby developers still, opposing to distributors, might want to build such 2494bb16672SJiri Slaby drivers to compile-test them. 2504bb16672SJiri Slaby 2514bb16672SJiri Slaby If you are a developer and want to build everything available, say Y 2524bb16672SJiri Slaby here. If you are a user/distributor, say N here to exclude useless 2534bb16672SJiri Slaby drivers to be distributed. 2544bb16672SJiri Slaby 2553fe617ccSLinus Torvaldsconfig WERROR 2563fe617ccSLinus Torvalds bool "Compile the kernel with warnings as errors" 257b339ec9cSMarco Elver default COMPILE_TEST 2583fe617ccSLinus Torvalds help 2593fe617ccSLinus Torvalds A kernel build should not cause any compiler warnings, and this 2602f7ab126SMiguel Ojeda enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 261e1789d7cSXin Li to enforce that rule by default. Certain warnings from other tools 262e1789d7cSXin Li such as the linker may be upgraded to errors with this option as 263e1789d7cSXin Li well. 2643fe617ccSLinus Torvalds 265e1789d7cSXin Li However, if you have a new (or very old) compiler or linker with odd 266e1789d7cSXin Li and unusual warnings, or you have some architecture with problems, 2673fe617ccSLinus Torvalds you may need to disable this config option in order to 2683fe617ccSLinus Torvalds successfully build the kernel. 2693fe617ccSLinus Torvalds 2703fe617ccSLinus Torvalds If in doubt, say Y. 2713fe617ccSLinus Torvalds 272d6fc9fcbSMasahiro Yamadaconfig UAPI_HEADER_TEST 273d6fc9fcbSMasahiro Yamada bool "Compile test UAPI headers" 2742a0a3080SThomas Weißschuh depends on HEADERS_INSTALL 275d6fc9fcbSMasahiro Yamada help 276d6fc9fcbSMasahiro Yamada Compile test headers exported to user-space to ensure they are 277d6fc9fcbSMasahiro Yamada self-contained, i.e. compilable as standalone units. 278d6fc9fcbSMasahiro Yamada 279d6fc9fcbSMasahiro Yamada If you are a developer or tester and want to ensure the exported 280d6fc9fcbSMasahiro Yamada headers are self-contained, say Y here. Otherwise, choose N. 281d6fc9fcbSMasahiro Yamada 2821da177e4SLinus Torvaldsconfig LOCALVERSION 2831da177e4SLinus Torvalds string "Local version - append to kernel release" 2841da177e4SLinus Torvalds help 2851da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 2861da177e4SLinus Torvalds This will show up when you type uname, for example. 2871da177e4SLinus Torvalds The string you set here will be appended after the contents of 2881da177e4SLinus Torvalds any files with a filename matching localversion* in your 2891da177e4SLinus Torvalds object and source tree, in that order. Your total string can 2901da177e4SLinus Torvalds be a maximum of 64 characters. 2911da177e4SLinus Torvalds 292aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 293aaebf433SRyan Anderson bool "Automatically append version information to the version string" 294aaebf433SRyan Anderson default y 295ac3339baSAlexey Dobriyan depends on !COMPILE_TEST 296aaebf433SRyan Anderson help 297aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 2986e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 2996e5a5420SRobert P. J. Day top of tree revision. 300aaebf433SRyan Anderson 301aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 3026e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 303aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 3046e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 305aaebf433SRyan Anderson 3060f9c608dSRasmus Villemoes (The actual string used here is the first 12 characters produced 3076e5a5420SRobert P. J. Day by running the command: 3086e5a5420SRobert P. J. Day 3096e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 3106e5a5420SRobert P. J. Day 3116e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 312aaebf433SRyan Anderson 3139afb719eSLaura Abbottconfig BUILD_SALT 3149afb719eSLaura Abbott string "Build ID Salt" 3159afb719eSLaura Abbott default "" 3169afb719eSLaura Abbott help 3179afb719eSLaura Abbott The build ID is used to link binaries and their debug info. Setting 3189afb719eSLaura Abbott this option will use the value in the calculation of the build id. 3199afb719eSLaura Abbott This is mostly useful for distributions which want to ensure the 3209afb719eSLaura Abbott build is unique between builds. It's safe to leave the default. 3219afb719eSLaura Abbott 3222e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 3232e9f3bddSH. Peter Anvin bool 3242e9f3bddSH. Peter Anvin 3252e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 3262e9f3bddSH. Peter Anvin bool 3272e9f3bddSH. Peter Anvin 3282e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 3292e9f3bddSH. Peter Anvin bool 3302e9f3bddSH. Peter Anvin 3313ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 3323ebe1243SLasse Collin bool 3333ebe1243SLasse Collin 3347dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 3357dd65febSAlbin Tonnerre bool 3367dd65febSAlbin Tonnerre 337e76e1fdfSKyungsik Leeconfig HAVE_KERNEL_LZ4 338e76e1fdfSKyungsik Lee bool 339e76e1fdfSKyungsik Lee 34048f7ddf7SNick Terrellconfig HAVE_KERNEL_ZSTD 34148f7ddf7SNick Terrell bool 34248f7ddf7SNick Terrell 343f16466afSVasily Gorbikconfig HAVE_KERNEL_UNCOMPRESSED 344f16466afSVasily Gorbik bool 345f16466afSVasily Gorbik 34630d65dbfSAlain Knaffchoice 34730d65dbfSAlain Knaff prompt "Kernel compression mode" 34830d65dbfSAlain Knaff default KERNEL_GZIP 34948f7ddf7SNick 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 35030d65dbfSAlain Knaff help 35130d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 35230d65dbfSAlain Knaff Several compression algorithms are available, which differ 35330d65dbfSAlain Knaff in efficiency, compression and decompression speed. 35430d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 35530d65dbfSAlain Knaff Decompression speed is relevant at each boot. 35630d65dbfSAlain Knaff 35730d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 35830d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 35930d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 36030d65dbfSAlain Knaff supplied by Christian Ludwig) 36130d65dbfSAlain Knaff 36230d65dbfSAlain Knaff High compression options are mostly useful for users, who 36330d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 36430d65dbfSAlain Knaff size matters less. 36530d65dbfSAlain Knaff 36630d65dbfSAlain Knaff If in doubt, select 'gzip' 36730d65dbfSAlain Knaff 36830d65dbfSAlain Knaffconfig KERNEL_GZIP 36930d65dbfSAlain Knaff bool "Gzip" 3702e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 37130d65dbfSAlain Knaff help 3727dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 3737dd65febSAlbin Tonnerre between compression ratio and decompression speed. 37430d65dbfSAlain Knaff 37530d65dbfSAlain Knaffconfig KERNEL_BZIP2 37630d65dbfSAlain Knaff bool "Bzip2" 3772e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 37830d65dbfSAlain Knaff help 37930d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 3800a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 3812e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 3822e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 3832e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 38430d65dbfSAlain Knaff 38530d65dbfSAlain Knaffconfig KERNEL_LZMA 38630d65dbfSAlain Knaff bool "LZMA" 3872e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 38830d65dbfSAlain Knaff help 3890a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 3900a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 3910a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 39230d65dbfSAlain Knaff 3933ebe1243SLasse Collinconfig KERNEL_XZ 3943ebe1243SLasse Collin bool "XZ" 3953ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 3963ebe1243SLasse Collin help 3973ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 3983ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 3993ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 4003ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 4017472ff8aSLasse Collin filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 4027472ff8aSLasse Collin and SPARC), XZ will create a few percent smaller kernel than 4037472ff8aSLasse Collin plain LZMA. 4043ebe1243SLasse Collin 4053ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 4063ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 4073ebe1243SLasse Collin and LZO. Compression is slow. 4083ebe1243SLasse Collin 4097dd65febSAlbin Tonnerreconfig KERNEL_LZO 4107dd65febSAlbin Tonnerre bool "LZO" 4117dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 4127dd65febSAlbin Tonnerre help 4130a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 414681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 4157dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 4167dd65febSAlbin Tonnerre 417e76e1fdfSKyungsik Leeconfig KERNEL_LZ4 418e76e1fdfSKyungsik Lee bool "LZ4" 419e76e1fdfSKyungsik Lee depends on HAVE_KERNEL_LZ4 420e76e1fdfSKyungsik Lee help 421e76e1fdfSKyungsik Lee LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 422e76e1fdfSKyungsik Lee A preliminary version of LZ4 de/compression tool is available at 423e76e1fdfSKyungsik Lee <https://code.google.com/p/lz4/>. 424e76e1fdfSKyungsik Lee 425e76e1fdfSKyungsik Lee Its compression ratio is worse than LZO. The size of the kernel 426e76e1fdfSKyungsik Lee is about 8% bigger than LZO. But the decompression speed is 427e76e1fdfSKyungsik Lee faster than LZO. 428e76e1fdfSKyungsik Lee 42948f7ddf7SNick Terrellconfig KERNEL_ZSTD 43048f7ddf7SNick Terrell bool "ZSTD" 43148f7ddf7SNick Terrell depends on HAVE_KERNEL_ZSTD 43248f7ddf7SNick Terrell help 43348f7ddf7SNick Terrell ZSTD is a compression algorithm targeting intermediate compression 43448f7ddf7SNick Terrell with fast decompression speed. It will compress better than GZIP and 43548f7ddf7SNick Terrell decompress around the same speed as LZO, but slower than LZ4. You 43648f7ddf7SNick Terrell will need at least 192 KB RAM or more for booting. The zstd command 43748f7ddf7SNick Terrell line tool is required for compression. 43848f7ddf7SNick Terrell 439f16466afSVasily Gorbikconfig KERNEL_UNCOMPRESSED 440f16466afSVasily Gorbik bool "None" 441f16466afSVasily Gorbik depends on HAVE_KERNEL_UNCOMPRESSED 442f16466afSVasily Gorbik help 443f16466afSVasily Gorbik Produce uncompressed kernel image. This option is usually not what 444f16466afSVasily Gorbik you want. It is useful for debugging the kernel in slow simulation 445f16466afSVasily Gorbik environments, where decompressing and moving the kernel is awfully 446f16466afSVasily Gorbik slow. This option allows early boot code to skip the decompressor 447f16466afSVasily Gorbik and jump right at uncompressed kernel image. 448f16466afSVasily Gorbik 44930d65dbfSAlain Knaffendchoice 45030d65dbfSAlain Knaff 451ada4ab7aSChris Downconfig DEFAULT_INIT 452ada4ab7aSChris Down string "Default init path" 453ada4ab7aSChris Down default "" 454ada4ab7aSChris Down help 455ada4ab7aSChris Down This option determines the default init for the system if no init= 456ada4ab7aSChris Down option is passed on the kernel command line. If the requested path is 457ada4ab7aSChris Down not present, we will still then move on to attempting further 458ada4ab7aSChris Down locations (e.g. /sbin/init, etc). If this is empty, we will just use 459ada4ab7aSChris Down the fallback list when init= is not passed. 460ada4ab7aSChris Down 461bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 462bd5dc17bSJosh Triplett string "Default hostname" 463bd5dc17bSJosh Triplett default "(none)" 464bd5dc17bSJosh Triplett help 465bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 466bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 467bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 468bd5dc17bSJosh Triplett system more usable with less configuration. 469bd5dc17bSJosh Triplett 4701da177e4SLinus Torvaldsconfig SYSVIPC 4711da177e4SLinus Torvalds bool "System V IPC" 472a7f7f624SMasahiro Yamada help 4731da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 4741da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 4751da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 4761da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 4771da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 4781da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 4791da177e4SLinus Torvalds you'll need to say Y here. 4801da177e4SLinus Torvalds 4811da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 4821da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 4831da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 4841da177e4SLinus Torvalds 485a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 486a5494dcdSEric W. Biederman bool 487a5494dcdSEric W. Biederman depends on SYSVIPC 488a5494dcdSEric W. Biederman depends on SYSCTL 489a5494dcdSEric W. Biederman default y 490a5494dcdSEric W. Biederman 4910cbed0eeSGuo Renconfig SYSVIPC_COMPAT 4920cbed0eeSGuo Ren def_bool y 4930cbed0eeSGuo Ren depends on COMPAT && SYSVIPC 4940cbed0eeSGuo Ren 4951da177e4SLinus Torvaldsconfig POSIX_MQUEUE 4961da177e4SLinus Torvalds bool "POSIX Message Queues" 49719c92399SKees Cook depends on NET 498a7f7f624SMasahiro Yamada help 4991da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 5001da177e4SLinus Torvalds queues every message has a priority which decides about succession 5011da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 5021da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 503b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 5041da177e4SLinus Torvalds 5051da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 5061da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 5071da177e4SLinus Torvalds operations on message queues. 5081da177e4SLinus Torvalds 5091da177e4SLinus Torvalds If unsure, say Y. 5101da177e4SLinus Torvalds 511bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 512bdc8e5f8SSerge E. Hallyn bool 513bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 514bdc8e5f8SSerge E. Hallyn depends on SYSCTL 515bdc8e5f8SSerge E. Hallyn default y 516bdc8e5f8SSerge E. Hallyn 517c73be61cSDavid Howellsconfig WATCH_QUEUE 518c73be61cSDavid Howells bool "General notification queue" 519c73be61cSDavid Howells default n 520c73be61cSDavid Howells help 521c73be61cSDavid Howells 522c73be61cSDavid Howells This is a general notification queue for the kernel to pass events to 523c73be61cSDavid Howells userspace by splicing them into pipes. It can be used in conjunction 524c73be61cSDavid Howells with watches for key/keyring change notifications and device 525c73be61cSDavid Howells notifications. 526c73be61cSDavid Howells 527c02b872aSMauro Carvalho Chehab See Documentation/core-api/watch_queue.rst 528c73be61cSDavid Howells 529226b4ccdSKonstantin Khlebnikovconfig CROSS_MEMORY_ATTACH 530226b4ccdSKonstantin Khlebnikov bool "Enable process_vm_readv/writev syscalls" 531226b4ccdSKonstantin Khlebnikov depends on MMU 532226b4ccdSKonstantin Khlebnikov default y 533226b4ccdSKonstantin Khlebnikov help 534226b4ccdSKonstantin Khlebnikov Enabling this option adds the system calls process_vm_readv and 535226b4ccdSKonstantin Khlebnikov process_vm_writev which allow a process with the correct privileges 536a2a368d9SGeert Uytterhoeven to directly read from or write to another process' address space. 537226b4ccdSKonstantin Khlebnikov See the man page for more details. 538226b4ccdSKonstantin Khlebnikov 5391da177e4SLinus Torvaldsconfig AUDIT 5401da177e4SLinus Torvalds bool "Auditing support" 541804a6a49SChris Wright depends on NET 5421da177e4SLinus Torvalds help 5431da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 5441da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 545cb74ed27SPaul Moore logging of avc messages output). System call auditing is included 546cb74ed27SPaul Moore on architectures which support it. 5471da177e4SLinus Torvalds 5487a017721SAKASHI Takahiroconfig HAVE_ARCH_AUDITSYSCALL 5497a017721SAKASHI Takahiro bool 5507a017721SAKASHI Takahiro 5511da177e4SLinus Torvaldsconfig AUDITSYSCALL 552cb74ed27SPaul Moore def_bool y 5537a017721SAKASHI Takahiro depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 55428a3a7ebSEric Paris select FSNOTIFY 55574c3cbe3SAl Viro 556d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 557764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 558b24abcffSDaniel Borkmannsource "kernel/bpf/Kconfig" 55987a4c375SChristoph Hellwigsource "kernel/Kconfig.preempt" 560d9817ebeSThomas Gleixner 561391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 562391dc69cSFrederic Weisbecker 563abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 564abf917cdSFrederic Weisbecker bool 565abf917cdSFrederic Weisbecker 566fdf9c356SFrederic Weisbeckerchoice 567fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 568b17006b4SJulian Braha default VIRT_CPU_ACCOUNTING_GEN if NO_HZ_FULL 56902382affSNicholas Piggin default TICK_CPU_ACCOUNTING 570fdf9c356SFrederic Weisbecker 571fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 572fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 573fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 574c58b0df1SFrederic Weisbecker depends on !S390 && !NO_HZ_FULL 575fdf9c356SFrederic Weisbecker help 576fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 577fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 578fdf9c356SFrederic Weisbecker granularity. 579fdf9c356SFrederic Weisbecker 580fdf9c356SFrederic Weisbecker If unsure, say Y. 581fdf9c356SFrederic Weisbecker 582abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE 583391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 584c58b0df1SFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 585abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 586391dc69cSFrederic Weisbecker help 587391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 588391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 589391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 590391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 591391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 592391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 593391dc69cSFrederic Weisbecker systems. 594391dc69cSFrederic Weisbecker 595abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN 596abf917cdSFrederic Weisbecker bool "Full dynticks CPU time accounting" 59724a9c541SFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING_USER 598554b0004SKevin Hilman depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 599041a1574SArnd Bergmann depends on GENERIC_CLOCKEVENTS 600abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 60124a9c541SFrederic Weisbecker select CONTEXT_TRACKING_USER 602abf917cdSFrederic Weisbecker help 603abf917cdSFrederic Weisbecker Select this option to enable task and CPU time accounting on full 604abf917cdSFrederic Weisbecker dynticks systems. This accounting is implemented by watching every 605abf917cdSFrederic Weisbecker kernel-user boundaries using the context tracking subsystem. 606abf917cdSFrederic Weisbecker The accounting is thus performed at the expense of some significant 607abf917cdSFrederic Weisbecker overhead. 608abf917cdSFrederic Weisbecker 609abf917cdSFrederic Weisbecker For now this is only useful if you are working on the full 610abf917cdSFrederic Weisbecker dynticks subsystem development. 611abf917cdSFrederic Weisbecker 612abf917cdSFrederic Weisbecker If unsure, say N. 613abf917cdSFrederic Weisbecker 614b58c3584SRik van Rielendchoice 615b58c3584SRik van Riel 616fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 617fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 618b58c3584SRik van Riel depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 619fdf9c356SFrederic Weisbecker help 620fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 621fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 622fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 623fdf9c356SFrederic Weisbecker small performance impact. 624fdf9c356SFrederic Weisbecker 625fdf9c356SFrederic Weisbecker If in doubt, say N here. 626fdf9c356SFrederic Weisbecker 62711d4afd4SVincent Guittotconfig HAVE_SCHED_AVG_IRQ 62811d4afd4SVincent Guittot def_bool y 62911d4afd4SVincent Guittot depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 63011d4afd4SVincent Guittot depends on SMP 63111d4afd4SVincent Guittot 632d4dbc991SVincent Guittotconfig SCHED_HW_PRESSURE 63398eb401dSValentin Schneider bool 634fcd7c9c3SValentin Schneider default y if ARM && ARM_CPU_TOPOLOGY 635fcd7c9c3SValentin Schneider default y if ARM64 63676504793SThara Gopinath depends on SMP 63798eb401dSValentin Schneider depends on CPU_FREQ_THERMAL 63898eb401dSValentin Schneider help 639d4dbc991SVincent Guittot Select this option to enable HW pressure accounting in the 640d4dbc991SVincent Guittot scheduler. HW pressure is the value conveyed to the scheduler 64198eb401dSValentin Schneider that reflects the reduction in CPU compute capacity resulted from 642d4dbc991SVincent Guittot HW throttling. HW throttling occurs when the performance of 643d4dbc991SVincent Guittot a CPU is capped due to high operating temperatures as an example. 64498eb401dSValentin Schneider 64598eb401dSValentin Schneider If selected, the scheduler will be able to balance tasks accordingly, 64698eb401dSValentin Schneider i.e. put less load on throttled CPUs than on non/less throttled ones. 64798eb401dSValentin Schneider 64898eb401dSValentin Schneider This requires the architecture to implement 649d4dbc991SVincent Guittot arch_update_hw_pressure() and arch_scale_thermal_pressure(). 65076504793SThara Gopinath 651391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 65246329a9dSJeff Layton bool "BSD Process Accounting (DEPRECATED)" 6532813893fSIulia Manda depends on MULTIUSER 65446329a9dSJeff Layton default n 655391dc69cSFrederic Weisbecker help 656391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 657391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 658391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 659391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 660391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 661391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 662391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 663391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 66446329a9dSJeff Layton information. This mechanism is antiquated and has significant 66546329a9dSJeff Layton scalability issues. You probably want to use eBPF instead. Say 66646329a9dSJeff Layton N unless you really need this. 667391dc69cSFrederic Weisbecker 668391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 669391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 670391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 671391dc69cSFrederic Weisbecker default n 672391dc69cSFrederic Weisbecker help 673391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 674391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 6753903bf94SRandy Dunlap process and its parent. Note that this file format is incompatible 676391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 677391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 678391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 679391dc69cSFrederic Weisbecker 680391dc69cSFrederic Weisbeckerconfig TASKSTATS 68119c92399SKees Cook bool "Export task/process statistics through netlink" 682391dc69cSFrederic Weisbecker depends on NET 6832813893fSIulia Manda depends on MULTIUSER 684391dc69cSFrederic Weisbecker default n 685391dc69cSFrederic Weisbecker help 686391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 687391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 688391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 689391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 690391dc69cSFrederic Weisbecker space on task exit. 691391dc69cSFrederic Weisbecker 692391dc69cSFrederic Weisbecker Say N if unsure. 693391dc69cSFrederic Weisbecker 694391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 69519c92399SKees Cook bool "Enable per-task delay accounting" 696391dc69cSFrederic Weisbecker depends on TASKSTATS 697f6db8347SNaveen N. Rao select SCHED_INFO 698391dc69cSFrederic Weisbecker help 699391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 700391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 701391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 702391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 703391dc69cSFrederic Weisbecker 704391dc69cSFrederic Weisbecker Say N if unsure. 705391dc69cSFrederic Weisbecker 706391dc69cSFrederic Weisbeckerconfig TASK_XACCT 70719c92399SKees Cook bool "Enable extended accounting over taskstats" 708391dc69cSFrederic Weisbecker depends on TASKSTATS 709391dc69cSFrederic Weisbecker help 710391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 711391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 712391dc69cSFrederic Weisbecker 713391dc69cSFrederic Weisbecker Say N if unsure. 714391dc69cSFrederic Weisbecker 715391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 71619c92399SKees Cook bool "Enable per-task storage I/O accounting" 717391dc69cSFrederic Weisbecker depends on TASK_XACCT 718391dc69cSFrederic Weisbecker help 719391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 720391dc69cSFrederic Weisbecker task has caused. 721391dc69cSFrederic Weisbecker 722391dc69cSFrederic Weisbecker Say N if unsure. 723391dc69cSFrederic Weisbecker 724eb414681SJohannes Weinerconfig PSI 725eb414681SJohannes Weiner bool "Pressure stall information tracking" 72698dfdd9eSRandy Dunlap select KERNFS 727eb414681SJohannes Weiner help 728eb414681SJohannes Weiner Collect metrics that indicate how overcommitted the CPU, memory, 729eb414681SJohannes Weiner and IO capacity are in the system. 730eb414681SJohannes Weiner 731eb414681SJohannes Weiner If you say Y here, the kernel will create /proc/pressure/ with the 732eb414681SJohannes Weiner pressure statistics files cpu, memory, and io. These will indicate 733eb414681SJohannes Weiner the share of walltime in which some or all tasks in the system are 734eb414681SJohannes Weiner delayed due to contention of the respective resource. 735eb414681SJohannes Weiner 7362ce7135aSJohannes Weiner In kernels with cgroup support, cgroups (cgroup2 only) will 7372ce7135aSJohannes Weiner have cpu.pressure, memory.pressure, and io.pressure files, 7382ce7135aSJohannes Weiner which aggregate pressure stalls for the grouped tasks only. 7392ce7135aSJohannes Weiner 740c3123552SMauro Carvalho Chehab For more details see Documentation/accounting/psi.rst. 741eb414681SJohannes Weiner 742eb414681SJohannes Weiner Say N if unsure. 743eb414681SJohannes Weiner 744e0c27447SJohannes Weinerconfig PSI_DEFAULT_DISABLED 745e0c27447SJohannes Weiner bool "Require boot parameter to enable pressure stall information tracking" 746e0c27447SJohannes Weiner default n 747e0c27447SJohannes Weiner depends on PSI 748e0c27447SJohannes Weiner help 749e0c27447SJohannes Weiner If set, pressure stall information tracking will be disabled 750428a1cb4SBaruch Siach per default but can be enabled through passing psi=1 on the 751428a1cb4SBaruch Siach kernel commandline during boot. 752e0c27447SJohannes Weiner 7537b2489d3SJohannes Weiner This feature adds some code to the task wakeup and sleep 7547b2489d3SJohannes Weiner paths of the scheduler. The overhead is too low to affect 7557b2489d3SJohannes Weiner common scheduling-intense workloads in practice (such as 7567b2489d3SJohannes Weiner webservers, memcache), but it does show up in artificial 7577b2489d3SJohannes Weiner scheduler stress tests, such as hackbench. 7587b2489d3SJohannes Weiner 7597b2489d3SJohannes Weiner If you are paranoid and not sure what the kernel will be 7607b2489d3SJohannes Weiner used for, say Y. 7617b2489d3SJohannes Weiner 7627b2489d3SJohannes Weiner Say N if unsure. 7637b2489d3SJohannes Weiner 764391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 765391dc69cSFrederic Weisbecker 7665c4991e2SFrederic Weisbeckerconfig CPU_ISOLATION 7675c4991e2SFrederic Weisbecker bool "CPU isolation" 76897577684SOleg Nesterov depends on SMP 7692c43838cSFrederic Weisbecker default y 7705c4991e2SFrederic Weisbecker help 7715c4991e2SFrederic Weisbecker Make sure that CPUs running critical tasks are not disturbed by 7725c4991e2SFrederic Weisbecker any source of "noise" such as unbound workqueues, timers, kthreads... 7732c43838cSFrederic Weisbecker Unbound jobs get offloaded to housekeeping CPUs. This is driven by 7742c43838cSFrederic Weisbecker the "isolcpus=" boot parameter. 7752c43838cSFrederic Weisbecker 7762c43838cSFrederic Weisbecker Say Y if unsure. 7775c4991e2SFrederic Weisbecker 7780af92d46SPaul E. McKenneysource "kernel/rcu/Kconfig" 779c903ff83SMike Travis 7801da177e4SLinus Torvaldsconfig IKCONFIG 781f2443ab6SRoss Biro tristate "Kernel .config support" 782a7f7f624SMasahiro Yamada help 7831da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 7841da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 7851da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 7861da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 7871da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 7881da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 7891da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 7901da177e4SLinus Torvalds /proc/config.gz if enabled (below). 7911da177e4SLinus Torvalds 7921da177e4SLinus Torvaldsconfig IKCONFIG_PROC 7931da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 7941da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 795a7f7f624SMasahiro Yamada help 7961da177e4SLinus Torvalds This option enables access to the kernel configuration file 7971da177e4SLinus Torvalds through /proc/config.gz. 7981da177e4SLinus Torvalds 799f7b101d3SJoel Fernandes (Google)config IKHEADERS 800f7b101d3SJoel Fernandes (Google) tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 801f7b101d3SJoel Fernandes (Google) depends on SYSFS 80243d8ce9dSJoel Fernandes (Google) help 803f7b101d3SJoel Fernandes (Google) This option enables access to the in-kernel headers that are generated during 804f7b101d3SJoel Fernandes (Google) the build process. These can be used to build eBPF tracing programs, 805f7b101d3SJoel Fernandes (Google) or similar programs. If you build the headers as a module, a module called 806f7b101d3SJoel Fernandes (Google) kheaders.ko is built which can be loaded on-demand to get access to headers. 80743d8ce9dSJoel Fernandes (Google) 808794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 809794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 8101c4b5ecbSChristoph Hellwig range 12 25 811f17a32e9SAdrian Bunk default 17 812361e9dfbSJosh Triplett depends on PRINTK 813794543a2SAlistair John Strachan help 81423b2899fSLuis R. Rodriguez Select the minimal kernel log buffer size as a power of 2. 81523b2899fSLuis R. Rodriguez The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 81623b2899fSLuis R. Rodriguez parameter, see below. Any higher size also might be forced 81723b2899fSLuis R. Rodriguez by "log_buf_len" boot parameter. 81823b2899fSLuis R. Rodriguez 819f17a32e9SAdrian Bunk Examples: 820f17a32e9SAdrian Bunk 17 => 128 KB 821f17a32e9SAdrian Bunk 16 => 64 KB 822f17a32e9SAdrian Bunk 15 => 32 KB 823f17a32e9SAdrian Bunk 14 => 16 KB 824794543a2SAlistair John Strachan 13 => 8 KB 825794543a2SAlistair John Strachan 12 => 4 KB 826794543a2SAlistair John Strachan 82723b2899fSLuis R. Rodriguezconfig LOG_CPU_MAX_BUF_SHIFT 82823b2899fSLuis R. Rodriguez int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 8292240a31dSGeert Uytterhoeven depends on SMP 83023b2899fSLuis R. Rodriguez range 0 21 83123b2899fSLuis R. Rodriguez default 0 if BASE_SMALL 832320bf431SYoann Congal default 12 833361e9dfbSJosh Triplett depends on PRINTK 83423b2899fSLuis R. Rodriguez help 83523b2899fSLuis R. Rodriguez This option allows to increase the default ring buffer size 83623b2899fSLuis R. Rodriguez according to the number of CPUs. The value defines the contribution 83723b2899fSLuis R. Rodriguez of each CPU as a power of 2. The used space is typically only few 83823b2899fSLuis R. Rodriguez lines however it might be much more when problems are reported, 83923b2899fSLuis R. Rodriguez e.g. backtraces. 84023b2899fSLuis R. Rodriguez 84123b2899fSLuis R. Rodriguez The increased size means that a new buffer has to be allocated and 84223b2899fSLuis R. Rodriguez the original static one is unused. It makes sense only on systems 84323b2899fSLuis R. Rodriguez with more CPUs. Therefore this value is used only when the sum of 84423b2899fSLuis R. Rodriguez contributions is greater than the half of the default kernel ring 84523b2899fSLuis R. Rodriguez buffer as defined by LOG_BUF_SHIFT. The default values are set 8460f7636e1SPaul Menzel so that more than 16 CPUs are needed to trigger the allocation. 84723b2899fSLuis R. Rodriguez 84823b2899fSLuis R. Rodriguez Also this option is ignored when "log_buf_len" kernel parameter is 84923b2899fSLuis R. Rodriguez used as it forces an exact (power of two) size of the ring buffer. 85023b2899fSLuis R. Rodriguez 85123b2899fSLuis R. Rodriguez The number of possible CPUs is used for this computation ignoring 8525e0d8d59SGeert Uytterhoeven hotplugging making the computation optimal for the worst case 8535e0d8d59SGeert Uytterhoeven scenario while allowing a simple algorithm to be used from bootup. 85423b2899fSLuis R. Rodriguez 85523b2899fSLuis R. Rodriguez Examples shift values and their meaning: 85623b2899fSLuis R. Rodriguez 17 => 128 KB for each CPU 85723b2899fSLuis R. Rodriguez 16 => 64 KB for each CPU 85823b2899fSLuis R. Rodriguez 15 => 32 KB for each CPU 85923b2899fSLuis R. Rodriguez 14 => 16 KB for each CPU 86023b2899fSLuis R. Rodriguez 13 => 8 KB for each CPU 86123b2899fSLuis R. Rodriguez 12 => 4 KB for each CPU 86223b2899fSLuis R. Rodriguez 86333701557SChris Downconfig PRINTK_INDEX 86433701557SChris Down bool "Printk indexing debugfs interface" 86533701557SChris Down depends on PRINTK && DEBUG_FS 86633701557SChris Down help 86733701557SChris Down Add support for indexing of all printk formats known at compile time 86833701557SChris Down at <debugfs>/printk/index/<module>. 86933701557SChris Down 87033701557SChris Down This can be used as part of maintaining daemons which monitor 87133701557SChris Down /dev/kmsg, as it permits auditing the printk formats present in a 87233701557SChris Down kernel, allowing detection of cases where monitored printks are 87333701557SChris Down changed or no longer present. 87433701557SChris Down 87533701557SChris Down There is no additional runtime cost to printk with this enabled. 87633701557SChris Down 8775cdc38f9SKAMEZAWA Hiroyuki# 8785cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 8795cdc38f9SKAMEZAWA Hiroyuki# 8805cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 8815cdc38f9SKAMEZAWA Hiroyuki bool 8825cdc38f9SKAMEZAWA Hiroyuki 88338ff87f7SStephen Boydconfig GENERIC_SCHED_CLOCK 88438ff87f7SStephen Boyd bool 88538ff87f7SStephen Boyd 88669842cbaSPatrick Bellasimenu "Scheduler features" 88769842cbaSPatrick Bellasi 88869842cbaSPatrick Bellasiconfig UCLAMP_TASK 88969842cbaSPatrick Bellasi bool "Enable utilization clamping for RT/FAIR tasks" 89069842cbaSPatrick Bellasi depends on CPU_FREQ_GOV_SCHEDUTIL 89169842cbaSPatrick Bellasi help 89269842cbaSPatrick Bellasi This feature enables the scheduler to track the clamped utilization 89369842cbaSPatrick Bellasi of each CPU based on RUNNABLE tasks scheduled on that CPU. 89469842cbaSPatrick Bellasi 89569842cbaSPatrick Bellasi With this option, the user can specify the min and max CPU 89669842cbaSPatrick Bellasi utilization allowed for RUNNABLE tasks. The max utilization defines 89769842cbaSPatrick Bellasi the maximum frequency a task should use while the min utilization 89869842cbaSPatrick Bellasi defines the minimum frequency it should use. 89969842cbaSPatrick Bellasi 90069842cbaSPatrick Bellasi Both min and max utilization clamp values are hints to the scheduler, 90169842cbaSPatrick Bellasi aiming at improving its frequency selection policy, but they do not 90269842cbaSPatrick Bellasi enforce or grant any specific bandwidth for tasks. 90369842cbaSPatrick Bellasi 90469842cbaSPatrick Bellasi If in doubt, say N. 90569842cbaSPatrick Bellasi 90669842cbaSPatrick Bellasiconfig UCLAMP_BUCKETS_COUNT 90769842cbaSPatrick Bellasi int "Number of supported utilization clamp buckets" 90869842cbaSPatrick Bellasi range 5 20 90969842cbaSPatrick Bellasi default 5 91069842cbaSPatrick Bellasi depends on UCLAMP_TASK 91169842cbaSPatrick Bellasi help 91269842cbaSPatrick Bellasi Defines the number of clamp buckets to use. The range of each bucket 91369842cbaSPatrick Bellasi will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 91469842cbaSPatrick Bellasi number of clamp buckets the finer their granularity and the higher 91569842cbaSPatrick Bellasi the precision of clamping aggregation and tracking at run-time. 91669842cbaSPatrick Bellasi 91769842cbaSPatrick Bellasi For example, with the minimum configuration value we will have 5 91869842cbaSPatrick Bellasi clamp buckets tracking 20% utilization each. A 25% boosted tasks will 91969842cbaSPatrick Bellasi be refcounted in the [20..39]% bucket and will set the bucket clamp 92069842cbaSPatrick Bellasi effective value to 25%. 92169842cbaSPatrick Bellasi If a second 30% boosted task should be co-scheduled on the same CPU, 92269842cbaSPatrick Bellasi that task will be refcounted in the same bucket of the first task and 92369842cbaSPatrick Bellasi it will boost the bucket clamp effective value to 30%. 92469842cbaSPatrick Bellasi The clamp effective value of a bucket is reset to its nominal value 92569842cbaSPatrick Bellasi (20% in the example above) when there are no more tasks refcounted in 92669842cbaSPatrick Bellasi that bucket. 92769842cbaSPatrick Bellasi 92869842cbaSPatrick Bellasi An additional boost/capping margin can be added to some tasks. In the 92969842cbaSPatrick Bellasi example above the 25% task will be boosted to 30% until it exits the 93069842cbaSPatrick Bellasi CPU. If that should be considered not acceptable on certain systems, 93169842cbaSPatrick Bellasi it's always possible to reduce the margin by increasing the number of 93269842cbaSPatrick Bellasi clamp buckets to trade off used memory for run-time tracking 93369842cbaSPatrick Bellasi precision. 93469842cbaSPatrick Bellasi 93569842cbaSPatrick Bellasi If in doubt, use the default value. 93669842cbaSPatrick Bellasi 93725c411fcSJohn Stultzconfig SCHED_PROXY_EXEC 93825c411fcSJohn Stultz bool "Proxy Execution" 93925c411fcSJohn Stultz # Avoid some build failures w/ PREEMPT_RT until it can be fixed 94025c411fcSJohn Stultz depends on !PREEMPT_RT 94125c411fcSJohn Stultz # Need to investigate how to inform sched_ext of split contexts 94225c411fcSJohn Stultz depends on !SCHED_CLASS_EXT 94325c411fcSJohn Stultz # Not particularly useful until we get to multi-rq proxying 94425c411fcSJohn Stultz depends on EXPERT 94525c411fcSJohn Stultz help 94625c411fcSJohn Stultz This option enables proxy execution, a mechanism for mutex-owning 94725c411fcSJohn Stultz tasks to inherit the scheduling context of higher priority waiters. 94825c411fcSJohn Stultz 94969842cbaSPatrick Bellasiendmenu 95069842cbaSPatrick Bellasi 951be3a7284SAndrea Arcangeli# 952c6f11553SKiryl Shutsemau (Meta)# For architectures that support present-but-inaccessible (PROT_NONE) page 953c6f11553SKiryl Shutsemau (Meta)# table entries detectable via pte_protnone() / pmd_protnone(): 954c6f11553SKiryl Shutsemau (Meta)# 955c6f11553SKiryl Shutsemau (Meta)config ARCH_HAS_PTE_PROTNONE 956c6f11553SKiryl Shutsemau (Meta) bool 957c6f11553SKiryl Shutsemau (Meta) 958c6f11553SKiryl Shutsemau (Meta)# 959be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler 960be3a7284SAndrea Arcangeli# balancing logic: 961be3a7284SAndrea Arcangeli# 962be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING 963be3a7284SAndrea Arcangeli bool 964be3a7284SAndrea Arcangeli 965be5e610cSPeter Zijlstra# 96672b252aeSMel Gorman# For architectures that prefer to flush all TLBs after a number of pages 96772b252aeSMel Gorman# are unmapped instead of sending one IPI per page to flush. The architecture 96872b252aeSMel Gorman# must provide guarantees on what happens if a clean TLB cache entry is 96972b252aeSMel Gorman# written after the unmap. Details are in mm/rmap.c near the check for 97072b252aeSMel Gorman# should_defer_flush. The architecture should also consider if the full flush 97172b252aeSMel Gorman# and the refill costs are offset by the savings of sending fewer IPIs. 97272b252aeSMel Gormanconfig ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 97372b252aeSMel Gorman bool 97472b252aeSMel Gorman 975c12d3362SArd Biesheuvelconfig CC_HAS_INT128 9763a7c7331SMasahiro Yamada def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 977c12d3362SArd Biesheuvel 978dee2b702SGustavo A. R. Silvaconfig CC_IMPLICIT_FALLTHROUGH 979dee2b702SGustavo A. R. Silva string 980158ea2d2SGustavo A. R. Silva default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 981dee2b702SGustavo A. R. Silva default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 982dee2b702SGustavo A. R. Silva 9830d3fccf6SNathan Chancellorconfig CC_MS_EXTENSIONS 9840d3fccf6SNathan Chancellor string 9850d3fccf6SNathan Chancellor default "-fms-anonymous-structs" if $(cc-option,-fms-anonymous-structs) 9860d3fccf6SNathan Chancellor default "-fms-extensions" 9870d3fccf6SNathan Chancellor 9883e00f580SKees Cook# Currently, disable gcc-10+ array-bounds globally. 9890da6e5fdSLinus Torvalds# It's still broken in gcc-13, so no upper bound yet. 9903e00f580SKees Cookconfig GCC10_NO_ARRAY_BOUNDS 9915a41237aSLinus Torvalds def_bool y 9925a41237aSLinus Torvalds 993f0be87c4SLinus Torvaldsconfig CC_NO_ARRAY_BOUNDS 994f0be87c4SLinus Torvalds bool 9958e5bd4eaSYury Norov default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 996f0be87c4SLinus Torvalds 99702153319SLinus Torvalds# Currently, disable -Wstringop-overflow for GCC globally. 99802153319SLinus Torvaldsconfig GCC_NO_STRINGOP_OVERFLOW 999a5e0ace0SGustavo A. R. Silva def_bool y 1000a5e0ace0SGustavo A. R. Silva 1001a5e0ace0SGustavo A. R. Silvaconfig CC_NO_STRINGOP_OVERFLOW 1002a5e0ace0SGustavo A. R. Silva bool 100302153319SLinus Torvalds default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 1004a5e0ace0SGustavo A. R. Silva 1005a5e0ace0SGustavo A. R. Silvaconfig CC_STRINGOP_OVERFLOW 1006a5e0ace0SGustavo A. R. Silva bool 1007a5e0ace0SGustavo A. R. Silva default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 1008a5e0ace0SGustavo A. R. Silva 100972b252aeSMel Gorman# 1010be5e610cSPeter Zijlstra# For architectures that know their GCC __int128 support is sound 1011be5e610cSPeter Zijlstra# 1012be5e610cSPeter Zijlstraconfig ARCH_SUPPORTS_INT128 1013be5e610cSPeter Zijlstra bool 1014be5e610cSPeter Zijlstra 1015be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions 1016be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH. 1017be3a7284SAndrea Arcangeli# 1018be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY 1019be3a7284SAndrea Arcangeli bool 1020be3a7284SAndrea Arcangeli 1021be3a7284SAndrea Arcangeliconfig NUMA_BALANCING 1022be3a7284SAndrea Arcangeli bool "Memory placement aware NUMA scheduler" 1023be3a7284SAndrea Arcangeli depends on ARCH_SUPPORTS_NUMA_BALANCING 1024c6f11553SKiryl Shutsemau (Meta) depends on ARCH_HAS_PTE_PROTNONE 1025be3a7284SAndrea Arcangeli depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 10266ebf98d7SDavid Hildenbrand (Arm) depends on SMP && NUMA_MIGRATION && !PREEMPT_RT 1027be3a7284SAndrea Arcangeli help 1028be3a7284SAndrea Arcangeli This option adds support for automatic NUMA aware memory/task placement. 1029be3a7284SAndrea Arcangeli The mechanism is quite primitive and is based on migrating memory when 10306d56a410SPaul Gortmaker it has references to the node the task is running on. 1031be3a7284SAndrea Arcangeli 1032be3a7284SAndrea Arcangeli This system will be inactive on UMA systems. 1033be3a7284SAndrea Arcangeli 1034df0d9847SPeter Zijlstra (Intel)config SCHED_CACHE 1035df0d9847SPeter Zijlstra (Intel) bool "Cache aware load balance" 1036df0d9847SPeter Zijlstra (Intel) default y 1037df0d9847SPeter Zijlstra (Intel) depends on SMP 1038df0d9847SPeter Zijlstra (Intel) help 1039df0d9847SPeter Zijlstra (Intel) When enabled, the scheduler will attempt to aggregate tasks from 1040df0d9847SPeter Zijlstra (Intel) the same process onto a single Last Level Cache (LLC) domain when 1041df0d9847SPeter Zijlstra (Intel) possible. This improves cache locality by keeping tasks that share 1042df0d9847SPeter Zijlstra (Intel) resources within the same cache domain, reducing cache misses and 1043df0d9847SPeter Zijlstra (Intel) lowering data access latency. 1044df0d9847SPeter Zijlstra (Intel) 10456f7c97e8SAneesh Kumar K.Vconfig NUMA_BALANCING_DEFAULT_ENABLED 10466f7c97e8SAneesh Kumar K.V bool "Automatically enable NUMA aware memory/task placement" 10476f7c97e8SAneesh Kumar K.V default y 10486f7c97e8SAneesh Kumar K.V depends on NUMA_BALANCING 10496f7c97e8SAneesh Kumar K.V help 10506f7c97e8SAneesh Kumar K.V If set, automatic NUMA balancing will be enabled if running on a NUMA 10516f7c97e8SAneesh Kumar K.V machine. 10526f7c97e8SAneesh Kumar K.V 105321c690a3SSuren Baghdasaryanconfig SLAB_OBJ_EXT 105421c690a3SSuren Baghdasaryan bool 105521c690a3SSuren Baghdasaryan 105623964d2dSLi Zefanmenuconfig CGROUPS 10576341e62bSChristoph Jaeger bool "Control Group support" 10582bd59d48STejun Heo select KERNFS 1059ddbcc7e8SPaul Menage help 106023964d2dSLi Zefan This option adds support for grouping sets of processes together, for 10615cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 10625cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 10635cdc38f9SKAMEZAWA Hiroyuki See 1064d6a3b247SMauro Carvalho Chehab - Documentation/scheduler/sched-design-CFS.rst (CFS) 1065da82c92fSMauro Carvalho Chehab - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 106645ce80fbSLi Zefan and resource control) 1067ddbcc7e8SPaul Menage 1068ddbcc7e8SPaul Menage Say N if unsure. 1069ddbcc7e8SPaul Menage 107023964d2dSLi Zefanif CGROUPS 107123964d2dSLi Zefan 10723e32cb2eSJohannes Weinerconfig PAGE_COUNTER 10733e32cb2eSJohannes Weiner bool 10743e32cb2eSJohannes Weiner 10756a010a49STejun Heoconfig CGROUP_FAVOR_DYNMODS 10766a010a49STejun Heo bool "Favor dynamic modification latency reduction by default" 10776a010a49STejun Heo help 10786a010a49STejun Heo This option enables the "favordynmods" mount option by default 10796a010a49STejun Heo which reduces the latencies of dynamic cgroup modifications such 10806a010a49STejun Heo as task migrations and controller on/offs at the cost of making 10816a010a49STejun Heo hot path operations such as forks and exits more expensive. 10826a010a49STejun Heo 10836a010a49STejun Heo Say N if unsure. 10846a010a49STejun Heo 1085c255a458SAndrew Mortonconfig MEMCG 1086a0166ec4SJohannes Weiner bool "Memory controller" 10873e32cb2eSJohannes Weiner select PAGE_COUNTER 108879bd9814STejun Heo select EVENTFD 108921c690a3SSuren Baghdasaryan select SLAB_OBJ_EXT 1090fdc5001bSKirill A. Shutemov select VM_EVENT_COUNTERS 109100f0b825SBalbir Singh help 1092a0166ec4SJohannes Weiner Provides control over the memory footprint of tasks in a cgroup. 109300f0b825SBalbir Singh 109425352d2fSShakeel Buttconfig MEMCG_NMI_UNSAFE 109525352d2fSShakeel Butt bool 109625352d2fSShakeel Butt depends on MEMCG 109725352d2fSShakeel Butt depends on HAVE_NMI 109825352d2fSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 109925352d2fSShakeel Butt default y 110025352d2fSShakeel Butt 1101940b01fcSShakeel Buttconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1102940b01fcSShakeel Butt bool 1103940b01fcSShakeel Butt depends on MEMCG 1104940b01fcSShakeel Butt depends on HAVE_NMI 1105940b01fcSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1106940b01fcSShakeel Butt default y 1107940b01fcSShakeel Butt 1108e93d4166SRoman Gushchinconfig MEMCG_V1 1109e93d4166SRoman Gushchin bool "Legacy cgroup v1 memory controller" 1110c9929f0eSVlastimil Babka depends on MEMCG 1111e93d4166SRoman Gushchin default n 1112e93d4166SRoman Gushchin help 1113e93d4166SRoman Gushchin Legacy cgroup v1 memory controller which has been deprecated by 1114e93d4166SRoman Gushchin cgroup v2 implementation. The v1 is there for legacy applications 1115e93d4166SRoman Gushchin which haven't migrated to the new cgroup v2 interface yet. If you 1116e93d4166SRoman Gushchin do not have any such application then you are completely fine leaving 1117e93d4166SRoman Gushchin this option disabled. 1118e93d4166SRoman Gushchin 1119e93d4166SRoman Gushchin Please note that feature set of the legacy memory controller is likely 1120e93d4166SRoman Gushchin going to shrink due to deprecation process. New deployments with v1 1121e93d4166SRoman Gushchin controller are highly discouraged. 1122e93d4166SRoman Gushchin 1123fcb4824bSValdis Kletnieks Say N if unsure. 112484c07d11SKirill Tkhai 11256bf024e6SJohannes Weinerconfig BLK_CGROUP 11266bf024e6SJohannes Weiner bool "IO controller" 11276bf024e6SJohannes Weiner depends on BLOCK 11282bc64a20SAneesh Kumar K.V default n 1129a7f7f624SMasahiro Yamada help 11306bf024e6SJohannes Weiner Generic block IO controller cgroup interface. This is the common 11316bf024e6SJohannes Weiner cgroup interface which should be used by various IO controlling 11326bf024e6SJohannes Weiner policies. 11332bc64a20SAneesh Kumar K.V 11346bf024e6SJohannes Weiner Currently, CFQ IO scheduler uses it to recognize task groups and 11356bf024e6SJohannes Weiner control disk bandwidth allocation (proportional time slice allocation) 11366bf024e6SJohannes Weiner to such task groups. It is also used by bio throttling logic in 11376bf024e6SJohannes Weiner block layer to implement upper limit in IO rates on a device. 1138e5d1367fSStephane Eranian 11396bf024e6SJohannes Weiner This option only enables generic Block IO controller infrastructure. 11406bf024e6SJohannes Weiner One needs to also enable actual IO controlling logic/policy. For 11416bf024e6SJohannes Weiner enabling proportional weight division of disk bandwidth in CFQ, set 11427baf2199SKrzysztof Kozlowski CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 11436bf024e6SJohannes Weiner CONFIG_BLK_DEV_THROTTLING=y. 11446bf024e6SJohannes Weiner 1145da82c92fSMauro Carvalho Chehab See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 11466bf024e6SJohannes Weiner 11476bf024e6SJohannes Weinerconfig CGROUP_WRITEBACK 11486bf024e6SJohannes Weiner bool 11496bf024e6SJohannes Weiner depends on MEMCG && BLK_CGROUP 11506bf024e6SJohannes Weiner default y 1151e5d1367fSStephane Eranian 11527c941438SDhaval Gianimenuconfig CGROUP_SCHED 1153a0166ec4SJohannes Weiner bool "CPU controller" 11547c941438SDhaval Giani default n 11557c941438SDhaval Giani help 11567c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 11577c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 11587c941438SDhaval Giani tasks. 11597c941438SDhaval Giani 11607c941438SDhaval Gianiif CGROUP_SCHED 1161e179e80cSTejun Heoconfig GROUP_SCHED_WEIGHT 1162e179e80cSTejun Heo def_bool n 1163e179e80cSTejun Heo 1164ddceadceSTejun Heoconfig GROUP_SCHED_BANDWIDTH 1165ddceadceSTejun Heo def_bool n 1166ddceadceSTejun Heo 11677c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 11687c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 11697c941438SDhaval Giani depends on CGROUP_SCHED 1170e179e80cSTejun Heo select GROUP_SCHED_WEIGHT 11717c941438SDhaval Giani default CGROUP_SCHED 11727c941438SDhaval Giani 1173ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 1174ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1175ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 1176ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 1177ab84d31eSPaul Turner default n 1178ab84d31eSPaul Turner help 1179ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 1180ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 1181ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 1182ab84d31eSPaul Turner restriction. 1183d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-bwc.rst for more information. 1184ab84d31eSPaul Turner 11857c941438SDhaval Gianiconfig RT_GROUP_SCHED 11867c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 11877c941438SDhaval Giani depends on CGROUP_SCHED 11887c941438SDhaval Giani default n 11897c941438SDhaval Giani help 11907c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 119132bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 11927c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 11937c941438SDhaval Giani realtime bandwidth for them. 1194d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-rt-group.rst for more information. 11957c941438SDhaval Giani 1196e34e0131SMichal Koutnýconfig RT_GROUP_SCHED_DEFAULT_DISABLED 1197e34e0131SMichal Koutný bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1198e34e0131SMichal Koutný depends on RT_GROUP_SCHED 1199e34e0131SMichal Koutný default n 1200e34e0131SMichal Koutný help 1201e34e0131SMichal Koutný When set, the RT group scheduling is disabled by default. The option 1202e34e0131SMichal Koutný is in inverted form so that mere RT_GROUP_SCHED enables the group 1203e34e0131SMichal Koutný scheduling. 1204e34e0131SMichal Koutný 1205e34e0131SMichal Koutný Say N if unsure. 1206e34e0131SMichal Koutný 120781951366STejun Heoconfig EXT_GROUP_SCHED 120881951366STejun Heo bool 120981951366STejun Heo depends on SCHED_CLASS_EXT && CGROUP_SCHED 121081951366STejun Heo select GROUP_SCHED_WEIGHT 1211ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 121281951366STejun Heo default y 121381951366STejun Heo 12147c941438SDhaval Gianiendif #CGROUP_SCHED 12157c941438SDhaval Giani 1216ebeca1f9STejun Heoconfig EXT_SUB_SCHED 1217ebeca1f9STejun Heo def_bool y 1218e73b1d72SCheng-Yang Chou depends on SCHED_CLASS_EXT && CGROUPS 1219ebeca1f9STejun Heo 1220af7f588dSMathieu Desnoyersconfig SCHED_MM_CID 1221af7f588dSMathieu Desnoyers def_bool y 1222af7f588dSMathieu Desnoyers depends on SMP && RSEQ 1223af7f588dSMathieu Desnoyers 12242480c093SPatrick Bellasiconfig UCLAMP_TASK_GROUP 12252480c093SPatrick Bellasi bool "Utilization clamping per group of tasks" 12262480c093SPatrick Bellasi depends on CGROUP_SCHED 12272480c093SPatrick Bellasi depends on UCLAMP_TASK 12282480c093SPatrick Bellasi default n 12292480c093SPatrick Bellasi help 12302480c093SPatrick Bellasi This feature enables the scheduler to track the clamped utilization 12312480c093SPatrick Bellasi of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 12322480c093SPatrick Bellasi 12332480c093SPatrick Bellasi When this option is enabled, the user can specify a min and max 12342480c093SPatrick Bellasi CPU bandwidth which is allowed for each single task in a group. 12352480c093SPatrick Bellasi The max bandwidth allows to clamp the maximum frequency a task 12362480c093SPatrick Bellasi can use, while the min bandwidth allows to define a minimum 12372480c093SPatrick Bellasi frequency a task will always use. 12382480c093SPatrick Bellasi 12392480c093SPatrick Bellasi When task group based utilization clamping is enabled, an eventually 12402480c093SPatrick Bellasi specified task-specific clamp value is constrained by the cgroup 12412480c093SPatrick Bellasi specified clamp value. Both minimum and maximum task clamping cannot 12422480c093SPatrick Bellasi be bigger than the corresponding clamping defined at task group level. 12432480c093SPatrick Bellasi 12442480c093SPatrick Bellasi If in doubt, say N. 12452480c093SPatrick Bellasi 12466bf024e6SJohannes Weinerconfig CGROUP_PIDS 12476bf024e6SJohannes Weiner bool "PIDs controller" 12486bf024e6SJohannes Weiner help 12496bf024e6SJohannes Weiner Provides enforcement of process number limits in the scope of a 12506bf024e6SJohannes Weiner cgroup. Any attempt to fork more processes than is allowed in the 12516bf024e6SJohannes Weiner cgroup will fail. PIDs are fundamentally a global resource because it 12526bf024e6SJohannes Weiner is fairly trivial to reach PID exhaustion before you reach even a 12536bf024e6SJohannes Weiner conservative kmemcg limit. As a result, it is possible to grind a 12546bf024e6SJohannes Weiner system to halt without being limited by other cgroup policies. The 12556cc578dfSParav Pandit PIDs controller is designed to stop this from happening. 12566bf024e6SJohannes Weiner 12576bf024e6SJohannes Weiner It should be noted that organisational operations (such as attaching 125898076833SJonathan Neuschäfer to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 12596bf024e6SJohannes Weiner since the PIDs limit only affects a process's ability to fork, not to 12606bf024e6SJohannes Weiner attach to a cgroup. 12616bf024e6SJohannes Weiner 126239d3e758SParav Panditconfig CGROUP_RDMA 126339d3e758SParav Pandit bool "RDMA controller" 126439d3e758SParav Pandit help 126539d3e758SParav Pandit Provides enforcement of RDMA resources defined by IB stack. 126639d3e758SParav Pandit It is fairly easy for consumers to exhaust RDMA resources, which 126739d3e758SParav Pandit can result into resource unavailability to other consumers. 126839d3e758SParav Pandit RDMA controller is designed to stop this from happening. 126939d3e758SParav Pandit Attaching processes with active RDMA resources to the cgroup 127039d3e758SParav Pandit hierarchy is allowed even if can cross the hierarchy's limit. 127139d3e758SParav Pandit 1272b168ed45SMaarten Lankhorstconfig CGROUP_DMEM 1273b168ed45SMaarten Lankhorst bool "Device memory controller (DMEM)" 1274e33b5149SMaxime Ripard select PAGE_COUNTER 1275b168ed45SMaarten Lankhorst help 1276b168ed45SMaarten Lankhorst The DMEM controller allows compatible devices to restrict device 1277b168ed45SMaarten Lankhorst memory usage based on the cgroup hierarchy. 1278b168ed45SMaarten Lankhorst 1279b168ed45SMaarten Lankhorst As an example, it allows you to restrict VRAM usage for applications 1280b168ed45SMaarten Lankhorst in the DRM subsystem. 1281b168ed45SMaarten Lankhorst 12826bf024e6SJohannes Weinerconfig CGROUP_FREEZER 12836bf024e6SJohannes Weiner bool "Freezer controller" 12846bf024e6SJohannes Weiner help 12856bf024e6SJohannes Weiner Provides a way to freeze and unfreeze all tasks in a 12866bf024e6SJohannes Weiner cgroup. 12876bf024e6SJohannes Weiner 1288489c2a20SJohannes Weiner This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1289489c2a20SJohannes Weiner controller includes important in-kernel memory consumers per default. 1290489c2a20SJohannes Weiner 1291489c2a20SJohannes Weiner If you're using cgroup2, say N. 1292489c2a20SJohannes Weiner 12936bf024e6SJohannes Weinerconfig CGROUP_HUGETLB 12946bf024e6SJohannes Weiner bool "HugeTLB controller" 12956bf024e6SJohannes Weiner depends on HUGETLB_PAGE 12966bf024e6SJohannes Weiner select PAGE_COUNTER 1297afc24d49SVivek Goyal default n 12986bf024e6SJohannes Weiner help 12996bf024e6SJohannes Weiner Provides a cgroup controller for HugeTLB pages. 13006bf024e6SJohannes Weiner When you enable this, you can put a per cgroup limit on HugeTLB usage. 13016bf024e6SJohannes Weiner The limit is enforced during page fault. Since HugeTLB doesn't 13026bf024e6SJohannes Weiner support page reclaim, enforcing the limit at page fault time implies 13036bf024e6SJohannes Weiner that, the application will get SIGBUS signal if it tries to access 13046bf024e6SJohannes Weiner HugeTLB pages beyond its limit. This requires the application to know 13056bf024e6SJohannes Weiner beforehand how much HugeTLB pages it would require for its use. The 13066bf024e6SJohannes Weiner control group is tracked in the third page lru pointer. This means 13076bf024e6SJohannes Weiner that we cannot use the controller with huge page less than 3 pages. 1308afc24d49SVivek Goyal 13096bf024e6SJohannes Weinerconfig CPUSETS 13106bf024e6SJohannes Weiner bool "Cpuset controller" 1311e1d4eeecSNicolas Pitre depends on SMP 1312bf9850f6SKuan-Wei Chiu select UNION_FIND 131323f09dccSFrederic Weisbecker select CPU_ISOLATION 13146bf024e6SJohannes Weiner help 13156bf024e6SJohannes Weiner This option will let you create and manage CPUSETs which 13166bf024e6SJohannes Weiner allow dynamically partitioning a system into sets of CPUs and 13176bf024e6SJohannes Weiner Memory Nodes and assigning tasks to run only within those sets. 13186bf024e6SJohannes Weiner This is primarily useful on large SMP or NUMA systems. 1319afc24d49SVivek Goyal 13206bf024e6SJohannes Weiner Say N if unsure. 1321afc24d49SVivek Goyal 13221abab1baSChen Ridongconfig CPUSETS_V1 13231abab1baSChen Ridong bool "Legacy cgroup v1 cpusets controller" 13241abab1baSChen Ridong depends on CPUSETS 13251abab1baSChen Ridong default n 13261abab1baSChen Ridong help 13271abab1baSChen Ridong Legacy cgroup v1 cpusets controller which has been deprecated by 13281abab1baSChen Ridong cgroup v2 implementation. The v1 is there for legacy applications 1329dae68fbaSMichal Koutný which haven't migrated to the new cgroup v2 interface yet. Legacy 1330dae68fbaSMichal Koutný interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 13311abab1baSChen Ridong do not have any such application then you are completely fine leaving 13321abab1baSChen Ridong this option disabled. 13331abab1baSChen Ridong 13341abab1baSChen Ridong Say N if unsure. 13351abab1baSChen Ridong 13366bf024e6SJohannes Weinerconfig PROC_PID_CPUSET 13376bf024e6SJohannes Weiner bool "Include legacy /proc/<pid>/cpuset file" 1338dae68fbaSMichal Koutný depends on CPUSETS_V1 133989e9b9e0STejun Heo default y 134089e9b9e0STejun Heo 13416bf024e6SJohannes Weinerconfig CGROUP_DEVICE 13426bf024e6SJohannes Weiner bool "Device controller" 13436bf024e6SJohannes Weiner help 13446bf024e6SJohannes Weiner Provides a cgroup controller implementing whitelists for 13456bf024e6SJohannes Weiner devices which a process in the cgroup can mknod or open. 13466bf024e6SJohannes Weiner 13476bf024e6SJohannes Weinerconfig CGROUP_CPUACCT 13486bf024e6SJohannes Weiner bool "Simple CPU accounting controller" 13496bf024e6SJohannes Weiner help 13506bf024e6SJohannes Weiner Provides a simple controller for monitoring the 13516bf024e6SJohannes Weiner total CPU consumed by the tasks in a cgroup. 13526bf024e6SJohannes Weiner 13536bf024e6SJohannes Weinerconfig CGROUP_PERF 13546bf024e6SJohannes Weiner bool "Perf controller" 13556bf024e6SJohannes Weiner depends on PERF_EVENTS 13566bf024e6SJohannes Weiner help 13576bf024e6SJohannes Weiner This option extends the perf per-cpu mode to restrict monitoring 13586bf024e6SJohannes Weiner to threads which belong to the cgroup specified and run on the 13596546b19fSNamhyung Kim designated cpu. Or this can be used to have cgroup ID in samples 13606546b19fSNamhyung Kim so that it can monitor performance events among cgroups. 13616bf024e6SJohannes Weiner 13626bf024e6SJohannes Weiner Say N if unsure. 13636bf024e6SJohannes Weiner 136430070984SDaniel Mackconfig CGROUP_BPF 136530070984SDaniel Mack bool "Support for eBPF programs attached to cgroups" 1366483c4933SAndy Lutomirski depends on BPF_SYSCALL 1367483c4933SAndy Lutomirski select SOCK_CGROUP_DATA 136830070984SDaniel Mack help 136930070984SDaniel Mack Allow attaching eBPF programs to a cgroup using the bpf(2) 137030070984SDaniel Mack syscall command BPF_PROG_ATTACH. 137130070984SDaniel Mack 137230070984SDaniel Mack In which context these programs are accessed depends on the type 137330070984SDaniel Mack of attachment. For instance, programs that are attached using 137430070984SDaniel Mack BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 137530070984SDaniel Mack inet sockets. 137630070984SDaniel Mack 1377a72232eaSVipin Sharmaconfig CGROUP_MISC 1378a72232eaSVipin Sharma bool "Misc resource controller" 1379a72232eaSVipin Sharma default n 1380a72232eaSVipin Sharma help 1381a72232eaSVipin Sharma Provides a controller for miscellaneous resources on a host. 1382a72232eaSVipin Sharma 1383a72232eaSVipin Sharma Miscellaneous scalar resources are the resources on the host system 1384a72232eaSVipin Sharma which cannot be abstracted like the other cgroups. This controller 1385a72232eaSVipin Sharma tracks and limits the miscellaneous resources used by a process 1386a72232eaSVipin Sharma attached to a cgroup hierarchy. 1387a72232eaSVipin Sharma 1388a72232eaSVipin Sharma For more information, please check misc cgroup section in 1389a72232eaSVipin Sharma /Documentation/admin-guide/cgroup-v2.rst. 1390a72232eaSVipin Sharma 13916bf024e6SJohannes Weinerconfig CGROUP_DEBUG 139223b0be48SWaiman Long bool "Debug controller" 13936bf024e6SJohannes Weiner default n 139423b0be48SWaiman Long depends on DEBUG_KERNEL 13956bf024e6SJohannes Weiner help 13966bf024e6SJohannes Weiner This option enables a simple controller that exports 139723b0be48SWaiman Long debugging information about the cgroups framework. This 139823b0be48SWaiman Long controller is for control cgroup debugging only. Its 139923b0be48SWaiman Long interfaces are not stable. 14006bf024e6SJohannes Weiner 14016bf024e6SJohannes Weiner Say N. 14026bf024e6SJohannes Weiner 140373b35147SArnd Bergmannconfig SOCK_CGROUP_DATA 140473b35147SArnd Bergmann bool 140573b35147SArnd Bergmann default n 140673b35147SArnd Bergmann 140723964d2dSLi Zefanendif # CGROUPS 1408c077719bSKAMEZAWA Hiroyuki 14098dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 14106a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 14112813893fSIulia Manda depends on MULTIUSER 14126a108a14SDavid Rientjes default !EXPERT 1413c5289a69SPavel Emelyanov help 1414c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 1415c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 1416c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 1417c5289a69SPavel Emelyanov different namespaces. 1418c5289a69SPavel Emelyanov 14198dd2a82cSDaniel Lezcanoif NAMESPACES 14208dd2a82cSDaniel Lezcano 142158bfdd6dSPavel Emelyanovconfig UTS_NS 142258bfdd6dSPavel Emelyanov bool "UTS namespace" 142317a6d441SDaniel Lezcano default y 142458bfdd6dSPavel Emelyanov help 142558bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 142658bfdd6dSPavel Emelyanov uname() system call 142758bfdd6dSPavel Emelyanov 1428769071acSAndrei Vaginconfig TIME_NS 1429769071acSAndrei Vagin bool "TIME namespace" 1430769071acSAndrei Vagin default y 1431769071acSAndrei Vagin help 1432769071acSAndrei Vagin In this namespace boottime and monotonic clocks can be set. 1433769071acSAndrei Vagin The time will keep going with the same pace. 1434769071acSAndrei Vagin 14351b6c8928SThomas Weißschuhconfig TIME_NS_VDSO 14361b6c8928SThomas Weißschuh def_bool TIME_NS && GENERIC_GETTIMEOFDAY 14371b6c8928SThomas Weißschuh 1438ae5e1b22SPavel Emelyanovconfig IPC_NS 1439ae5e1b22SPavel Emelyanov bool "IPC namespace" 14408dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 144117a6d441SDaniel Lezcano default y 1442ae5e1b22SPavel Emelyanov help 1443ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 1444614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 1445ae5e1b22SPavel Emelyanov 1446aee16ce7SPavel Emelyanovconfig USER_NS 144719c92399SKees Cook bool "User namespace" 14485673a94cSEric W. Biederman default n 1449aee16ce7SPavel Emelyanov help 1450aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 1451aee16ce7SPavel Emelyanov to provide different user info for different servers. 1452e11f0ae3SEric W. Biederman 1453e11f0ae3SEric W. Biederman When user namespaces are enabled in the kernel it is 1454d886f4e4SJohannes Weiner recommended that the MEMCG option also be enabled and that 1455d886f4e4SJohannes Weiner user-space use the memory control groups to limit the amount 1456d886f4e4SJohannes Weiner of memory a memory unprivileged users can use. 1457e11f0ae3SEric W. Biederman 1458aee16ce7SPavel Emelyanov If unsure, say N. 1459aee16ce7SPavel Emelyanov 146074bd59bbSPavel Emelyanovconfig PID_NS 14619bd38c2cSDaniel Lezcano bool "PID Namespaces" 146217a6d441SDaniel Lezcano default y 146374bd59bbSPavel Emelyanov help 146412d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 1465692105b8SMatt LaPlante processes with the same pid as long as they are in different 146674bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 146774bd59bbSPavel Emelyanov 1468d6eb633fSMatt Helsleyconfig NET_NS 1469d6eb633fSMatt Helsley bool "Network namespace" 14708dd2a82cSDaniel Lezcano depends on NET 147117a6d441SDaniel Lezcano default y 1472d6eb633fSMatt Helsley help 1473d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 1474d6eb633fSMatt Helsley of the network stack. 1475d6eb633fSMatt Helsley 14768dd2a82cSDaniel Lezcanoendif # NAMESPACES 14778dd2a82cSDaniel Lezcano 14785cb366bbSAdrian Reberconfig CHECKPOINT_RESTORE 14795cb366bbSAdrian Reber bool "Checkpoint/restore support" 148030341ec9SRen Zhijie depends on PROC_FS 14815cb366bbSAdrian Reber select PROC_CHILDREN 1482bfe3911aSChris Wilson select KCMP 14835cb366bbSAdrian Reber default n 14845cb366bbSAdrian Reber help 14855cb366bbSAdrian Reber Enables additional kernel features in a sake of checkpoint/restore. 14865cb366bbSAdrian Reber In particular it adds auxiliary prctl codes to setup process text, 14875cb366bbSAdrian Reber data and heap segment sizes, and a few additional /proc filesystem 14885cb366bbSAdrian Reber entries. 14895cb366bbSAdrian Reber 14905cb366bbSAdrian Reber If unsure, say N here. 14915cb366bbSAdrian Reber 14925091faa4SMike Galbraithconfig SCHED_AUTOGROUP 14935091faa4SMike Galbraith bool "Automatic process group scheduling" 14945091faa4SMike Galbraith select CGROUPS 14955091faa4SMike Galbraith select CGROUP_SCHED 14965091faa4SMike Galbraith select FAIR_GROUP_SCHED 14975091faa4SMike Galbraith help 14985091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 14995091faa4SMike Galbraith automatically creating and populating task groups. This separation 15005091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 15015091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 15025091faa4SMike Galbraith upon task session. 15035091faa4SMike Galbraith 15047af37becSDaniel Lezcanoconfig RELAY 15057af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 150626b5679eSPeter Zijlstra select IRQ_WORK 15077af37becSDaniel Lezcano help 15087af37becSDaniel Lezcano This option enables support for relay interface support in 15097af37becSDaniel Lezcano certain file systems (such as debugfs). 15107af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 15117af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 15127af37becSDaniel Lezcano user space. 15137af37becSDaniel Lezcano 15147af37becSDaniel Lezcano If unsure, say N. 15157af37becSDaniel Lezcano 1516f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1517f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1518f991633dSDimitri Gorokhovik help 1519f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1520f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1521f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1522f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 15238c27ceffSMauro Carvalho Chehab etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1524f991633dSDimitri Gorokhovik 1525f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1526f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1527f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1528f991633dSDimitri Gorokhovik 1529f991633dSDimitri Gorokhovik If unsure say Y. 1530f991633dSDimitri Gorokhovik 1531c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1532c33df4eaSJean-Paul Saman 1533dbec4866SSam Ravnborgsource "usr/Kconfig" 1534dbec4866SSam Ravnborg 1535c33df4eaSJean-Paul Samanendif 1536c33df4eaSJean-Paul Saman 153776db5a27SMasami Hiramatsuconfig BOOT_CONFIG 153876db5a27SMasami Hiramatsu bool "Boot config support" 1539a2a9d67aSMasami Hiramatsu select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 154076db5a27SMasami Hiramatsu help 154176db5a27SMasami Hiramatsu Extra boot config allows system admin to pass a config file as 154276db5a27SMasami Hiramatsu complemental extension of kernel cmdline when booting. 15430947db01SMasami Hiramatsu The boot config file must be attached at the end of initramfs 154485c46b78SMasami Hiramatsu with checksum, size and magic word. 15450947db01SMasami Hiramatsu See <file:Documentation/admin-guide/bootconfig.rst> for details. 154676db5a27SMasami Hiramatsu 154776db5a27SMasami Hiramatsu If unsure, say Y. 154876db5a27SMasami Hiramatsu 1549b743852cSPaul E. McKenneyconfig BOOT_CONFIG_FORCE 1550b743852cSPaul E. McKenney bool "Force unconditional bootconfig processing" 1551b743852cSPaul E. McKenney depends on BOOT_CONFIG 15526ded8a28SPaul E. McKenney default y if BOOT_CONFIG_EMBED 1553b743852cSPaul E. McKenney help 1554b743852cSPaul E. McKenney With this Kconfig option set, BOOT_CONFIG processing is carried 1555b743852cSPaul E. McKenney out even when the "bootconfig" kernel-boot parameter is omitted. 1556b743852cSPaul E. McKenney In fact, with this Kconfig option set, there is no way to 1557b743852cSPaul E. McKenney make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1558b743852cSPaul E. McKenney parameters. 1559b743852cSPaul E. McKenney 1560b743852cSPaul E. McKenney If unsure, say N. 1561b743852cSPaul E. McKenney 1562a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED 1563a2a9d67aSMasami Hiramatsu bool "Embed bootconfig file in the kernel" 1564a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG 1565a2a9d67aSMasami Hiramatsu help 1566a2a9d67aSMasami Hiramatsu Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1567a2a9d67aSMasami Hiramatsu kernel. Usually, the bootconfig file is loaded with the initrd 1568a2a9d67aSMasami Hiramatsu image. But if the system doesn't support initrd, this option will 1569a2a9d67aSMasami Hiramatsu help you by embedding a bootconfig file while building the kernel. 1570a2a9d67aSMasami Hiramatsu 1571a2a9d67aSMasami Hiramatsu If unsure, say N. 1572a2a9d67aSMasami Hiramatsu 1573a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED_FILE 1574a2a9d67aSMasami Hiramatsu string "Embedded bootconfig file path" 1575a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG_EMBED 1576a2a9d67aSMasami Hiramatsu help 1577a2a9d67aSMasami Hiramatsu Specify a bootconfig file which will be embedded to the kernel. 1578a2a9d67aSMasami Hiramatsu This bootconfig will be used if there is no initrd or no other 1579a2a9d67aSMasami Hiramatsu bootconfig in the initrd. 1580a2a9d67aSMasami Hiramatsu 1581*fc9d9047SBreno Leitaoconfig ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG 1582*fc9d9047SBreno Leitao bool 1583*fc9d9047SBreno Leitao help 1584*fc9d9047SBreno Leitao Silent symbol; no C code reads it directly. Architectures 1585*fc9d9047SBreno Leitao select it once their setup_arch() calls 1586*fc9d9047SBreno Leitao xbc_prepend_embedded_cmdline() before parse_early_param(). 1587*fc9d9047SBreno Leitao Its only role is to gate the user-visible 1588*fc9d9047SBreno Leitao CMDLINE_FROM_BOOTCONFIG option per-arch, the same 1589*fc9d9047SBreno Leitao ARCH_SUPPORTS_* idiom used by ARCH_SUPPORTS_CFI, etc. 1590*fc9d9047SBreno Leitao 1591*fc9d9047SBreno Leitaoconfig CMDLINE_FROM_BOOTCONFIG 1592*fc9d9047SBreno Leitao bool "Render embedded bootconfig as kernel cmdline at build time" 1593*fc9d9047SBreno Leitao depends on BOOT_CONFIG_EMBED_FILE != "" 1594*fc9d9047SBreno Leitao depends on ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG 1595*fc9d9047SBreno Leitao depends on CMDLINE = "" 1596*fc9d9047SBreno Leitao default n 1597*fc9d9047SBreno Leitao help 1598*fc9d9047SBreno Leitao Render the "kernel" subtree of the embedded bootconfig file into a 1599*fc9d9047SBreno Leitao flat cmdline string at kernel build time and prepend it to 1600*fc9d9047SBreno Leitao boot_command_line during early architecture setup. This makes 1601*fc9d9047SBreno Leitao early_param() handlers (e.g. mem=, earlycon=, loglevel=) see the 1602*fc9d9047SBreno Leitao values supplied via the embedded bootconfig. 1603*fc9d9047SBreno Leitao 1604*fc9d9047SBreno Leitao The runtime bootconfig parser is unaffected, so tree-structured 1605*fc9d9047SBreno Leitao consumers such as ftrace boot-time tracing keep working. 1606*fc9d9047SBreno Leitao 1607*fc9d9047SBreno Leitao Note: when an initrd also carries a bootconfig, its "kernel" 1608*fc9d9047SBreno Leitao subtree is still parsed at runtime, but the embedded "kernel" 1609*fc9d9047SBreno Leitao keys remain in boot_command_line for parse_early_param() and 1610*fc9d9047SBreno Leitao end up later than the initrd keys in saved_command_line, so 1611*fc9d9047SBreno Leitao parse_args() last-wins favors the embedded values. If you need 1612*fc9d9047SBreno Leitao initrd to override embedded kernel.* keys, leave this option 1613*fc9d9047SBreno Leitao off. 1614*fc9d9047SBreno Leitao 1615*fc9d9047SBreno Leitao If unsure, say N. 1616*fc9d9047SBreno Leitao 1617032a7302SDouglas Andersonconfig CMDLINE_LOG_WRAP_IDEAL_LEN 1618032a7302SDouglas Anderson int "Length to try to wrap the cmdline when logged at boot" 1619032a7302SDouglas Anderson default 1021 1620032a7302SDouglas Anderson range 0 1021 1621032a7302SDouglas Anderson help 1622032a7302SDouglas Anderson At boot time, the kernel command line is logged to the console. 1623032a7302SDouglas Anderson The log message will start with the prefix "Kernel command line: ". 1624032a7302SDouglas Anderson The log message will attempt to be wrapped (split into multiple log 1625032a7302SDouglas Anderson messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1626032a7302SDouglas Anderson If wrapping happens, each log message will start with the prefix and 1627032a7302SDouglas Anderson all but the last message will end with " \". Messages may exceed the 1628032a7302SDouglas Anderson ideal length if a place to wrap isn't found before the specified 1629032a7302SDouglas Anderson number of characters. 1630032a7302SDouglas Anderson 1631032a7302SDouglas Anderson A value of 0 disables wrapping, though be warned that the maximum 1632032a7302SDouglas Anderson length of a log message (1021 characters) may cause the cmdline to 1633032a7302SDouglas Anderson be truncated. 1634032a7302SDouglas Anderson 16351274aea1SDavid Disseldorpconfig INITRAMFS_PRESERVE_MTIME 16361274aea1SDavid Disseldorp bool "Preserve cpio archive mtimes in initramfs" 163774792608SGeert Uytterhoeven depends on BLK_DEV_INITRD 16381274aea1SDavid Disseldorp default y 16391274aea1SDavid Disseldorp help 16401274aea1SDavid Disseldorp Each entry in an initramfs cpio archive carries an mtime value. When 16411274aea1SDavid Disseldorp enabled, extracted cpio items take this mtime, with directory mtime 16421274aea1SDavid Disseldorp setting deferred until after creation of any child entries. 16431274aea1SDavid Disseldorp 16441274aea1SDavid Disseldorp If unsure, say Y. 16451274aea1SDavid Disseldorp 164683c0b272SDavid Disseldorpconfig INITRAMFS_TEST 164783c0b272SDavid Disseldorp bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 164883c0b272SDavid Disseldorp depends on BLK_DEV_INITRD && KUNIT=y 164983c0b272SDavid Disseldorp default KUNIT_ALL_TESTS 165083c0b272SDavid Disseldorp help 165183c0b272SDavid Disseldorp Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 165283c0b272SDavid Disseldorp 1653877417e6SArnd Bergmannchoice 1654877417e6SArnd Bergmann prompt "Compiler optimization level" 16552cc3ce24SUlf Magnusson default CC_OPTIMIZE_FOR_PERFORMANCE 1656877417e6SArnd Bergmann 1657877417e6SArnd Bergmannconfig CC_OPTIMIZE_FOR_PERFORMANCE 165815f5db60SMasahiro Yamada bool "Optimize for performance (-O2)" 1659877417e6SArnd Bergmann help 1660877417e6SArnd Bergmann This is the default optimization level for the kernel, building 1661877417e6SArnd Bergmann with the "-O2" compiler flag for best performance and most 1662877417e6SArnd Bergmann helpful compile-time warnings. 1663877417e6SArnd Bergmann 1664c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 166515f5db60SMasahiro Yamada bool "Optimize for size (-Os)" 1666c45b4f1fSLinus Torvalds help 1667ce3b487fSMasahiro Yamada Choosing this option will pass "-Os" to your compiler resulting 1668ce3b487fSMasahiro Yamada in a smaller kernel. 1669c45b4f1fSLinus Torvalds 1670877417e6SArnd Bergmannendchoice 1671877417e6SArnd Bergmann 16725d20ee31SNicholas Pigginconfig HAVE_LD_DEAD_CODE_DATA_ELIMINATION 16735d20ee31SNicholas Piggin bool 16745d20ee31SNicholas Piggin help 16755d20ee31SNicholas Piggin This requires that the arch annotates or otherwise protects 16765d20ee31SNicholas Piggin its external entry points from being discarded. Linker scripts 16775d20ee31SNicholas Piggin must also merge .text.*, .data.*, and .bss.* correctly into 16785d20ee31SNicholas Piggin output sections. Care must be taken not to pull in unrelated 16795d20ee31SNicholas Piggin sections (e.g., '.text.init'). Typically '.' in section names 16805d20ee31SNicholas Piggin is used to distinguish them from label names / C identifiers. 16815d20ee31SNicholas Piggin 16825d20ee31SNicholas Pigginconfig LD_DEAD_CODE_DATA_ELIMINATION 16835d20ee31SNicholas Piggin bool "Dead code and data elimination (EXPERIMENTAL)" 16845d20ee31SNicholas Piggin depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 16855d20ee31SNicholas Piggin depends on EXPERT 1686e85d1d65SMasahiro Yamada depends on $(cc-option,-ffunction-sections -fdata-sections) 1687e85d1d65SMasahiro Yamada depends on $(ld-option,--gc-sections) 16885d20ee31SNicholas Piggin help 16898b9d2712SMasahiro Yamada Enable this if you want to do dead code and data elimination with 16908b9d2712SMasahiro Yamada the linker by compiling with -ffunction-sections -fdata-sections, 16918b9d2712SMasahiro Yamada and linking with --gc-sections. 16925d20ee31SNicholas Piggin 16935d20ee31SNicholas Piggin This can reduce on disk and in-memory size of the kernel 16945d20ee31SNicholas Piggin code and static data, particularly for small configs and 16955d20ee31SNicholas Piggin on small systems. This has the possibility of introducing 16965d20ee31SNicholas Piggin silently broken kernel if the required annotations are not 16975d20ee31SNicholas Piggin present. This option is not well tested yet, so use at your 16985d20ee31SNicholas Piggin own risk. 16995d20ee31SNicholas Piggin 170059612b24SNathan Chancellorconfig LD_ORPHAN_WARN 170159612b24SNathan Chancellor def_bool y 170259612b24SNathan Chancellor depends on ARCH_WANT_LD_ORPHAN_WARN 170359612b24SNathan Chancellor depends on $(ld-option,--orphan-handling=warn) 1704e1789d7cSXin Li depends on $(ld-option,--orphan-handling=error) 1705e1789d7cSXin Li 1706e1789d7cSXin Liconfig LD_ORPHAN_WARN_LEVEL 1707e1789d7cSXin Li string 1708e1789d7cSXin Li depends on LD_ORPHAN_WARN 1709e1789d7cSXin Li default "error" if WERROR 1710e1789d7cSXin Li default "warn" 171159612b24SNathan Chancellor 1712657a5209SMike Frysingerconfig HAVE_UID16 1713657a5209SMike Frysinger bool 1714657a5209SMike Frysinger 1715657a5209SMike Frysingerconfig SYSCTL_EXCEPTION_TRACE 1716657a5209SMike Frysinger bool 1717657a5209SMike Frysinger help 1718657a5209SMike Frysinger Enable support for /proc/sys/debug/exception-trace. 1719657a5209SMike Frysinger 1720657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_NO_WARN 1721657a5209SMike Frysinger bool 1722657a5209SMike Frysinger help 1723657a5209SMike Frysinger Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1724657a5209SMike Frysinger Allows arch to define/use @no_unaligned_warning to possibly warn 1725657a5209SMike Frysinger about unaligned access emulation going on under the hood. 1726657a5209SMike Frysinger 1727657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_ALLOW 1728657a5209SMike Frysinger bool 1729657a5209SMike Frysinger help 1730657a5209SMike Frysinger Enable support for /proc/sys/kernel/unaligned-trap 1731657a5209SMike Frysinger Allows arches to define/use @unaligned_enabled to runtime toggle 1732657a5209SMike Frysinger the unaligned access emulation. 1733657a5209SMike Frysinger see arch/parisc/kernel/unaligned.c for reference 1734657a5209SMike Frysinger 1735c443279aSChristian Braunerconfig SYSFS_SYSCALL 1736c443279aSChristian Brauner bool "Sysfs syscall support" 1737c443279aSChristian Brauner default n 1738c443279aSChristian Brauner help 1739c443279aSChristian Brauner sys_sysfs is an obsolete system call no longer supported in libc. 1740c443279aSChristian Brauner Note that disabling this option is more secure but might break 1741c443279aSChristian Brauner compatibility with some systems. 1742c443279aSChristian Brauner 1743c443279aSChristian Brauner If unsure say N here. 1744c443279aSChristian Brauner 1745657a5209SMike Frysingerconfig HAVE_PCSPKR_PLATFORM 1746657a5209SMike Frysinger bool 1747657a5209SMike Frysinger 17486a108a14SDavid Rientjesmenuconfig EXPERT 17496a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1750f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1751f505c553SJosh Triplett select DEBUG_KERNEL 17521da177e4SLinus Torvalds help 17531da177e4SLinus Torvalds This option allows certain base kernel options and settings 17541da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 17551da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 17561da177e4SLinus Torvalds Only use this if you really know what you are doing. 17571da177e4SLinus Torvalds 1758ae81f9e3SChuck Ebbertconfig UID16 17596a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 17602813893fSIulia Manda depends on HAVE_UID16 && MULTIUSER 1761ae81f9e3SChuck Ebbert default y 1762ae81f9e3SChuck Ebbert help 1763ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1764ae81f9e3SChuck Ebbert 17652813893fSIulia Mandaconfig MULTIUSER 17662813893fSIulia Manda bool "Multiple users, groups and capabilities support" if EXPERT 17672813893fSIulia Manda default y 17682813893fSIulia Manda help 17692813893fSIulia Manda This option enables support for non-root users, groups and 17702813893fSIulia Manda capabilities. 17712813893fSIulia Manda 17722813893fSIulia Manda If you say N here, all processes will run with UID 0, GID 0, and all 17732813893fSIulia Manda possible capabilities. Saying N here also compiles out support for 17742813893fSIulia Manda system calls related to UIDs, GIDs, and capabilities, such as setuid, 17752813893fSIulia Manda setgid, and capset. 17762813893fSIulia Manda 17772813893fSIulia Manda If unsure, say Y here. 17782813893fSIulia Manda 1779f6187769SFabian Frederickconfig SGETMASK_SYSCALL 1780f6187769SFabian Frederick bool "sgetmask/ssetmask syscalls support" if EXPERT 1781cd14b018SMasahiro Yamada default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1782a7f7f624SMasahiro Yamada help 1783f6187769SFabian Frederick sys_sgetmask and sys_ssetmask are obsolete system calls 1784f6187769SFabian Frederick no longer supported in libc but still enabled by default in some 1785f6187769SFabian Frederick architectures. 1786f6187769SFabian Frederick 1787f6187769SFabian Frederick If unsure, leave the default option here. 1788f6187769SFabian Frederick 1789d1b069f5SRandy Dunlapconfig FHANDLE 1790d1b069f5SRandy Dunlap bool "open by fhandle syscalls" if EXPERT 1791d1b069f5SRandy Dunlap select EXPORTFS 1792d1b069f5SRandy Dunlap default y 1793d1b069f5SRandy Dunlap help 1794d1b069f5SRandy Dunlap If you say Y here, a user level program will be able to map 1795d1b069f5SRandy Dunlap file names to handle and then later use the handle for 1796d1b069f5SRandy Dunlap different file system operations. This is useful in implementing 1797d1b069f5SRandy Dunlap userspace file servers, which now track files using handles instead 1798d1b069f5SRandy Dunlap of names. The handle would remain the same even if file names 1799d1b069f5SRandy Dunlap get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1800d1b069f5SRandy Dunlap syscalls. 1801d1b069f5SRandy Dunlap 1802baa73d9eSNicolas Pitreconfig POSIX_TIMERS 1803baa73d9eSNicolas Pitre bool "Posix Clocks & timers" if EXPERT 1804baa73d9eSNicolas Pitre default y 1805baa73d9eSNicolas Pitre help 1806baa73d9eSNicolas Pitre This includes native support for POSIX timers to the kernel. 1807baa73d9eSNicolas Pitre Some embedded systems have no use for them and therefore they 1808baa73d9eSNicolas Pitre can be configured out to reduce the size of the kernel image. 1809baa73d9eSNicolas Pitre 1810baa73d9eSNicolas Pitre When this option is disabled, the following syscalls won't be 1811baa73d9eSNicolas Pitre available: timer_create, timer_gettime: timer_getoverrun, 1812baa73d9eSNicolas Pitre timer_settime, timer_delete, clock_adjtime, getitimer, 1813baa73d9eSNicolas Pitre setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1814baa73d9eSNicolas Pitre clock_getres and clock_nanosleep syscalls will be limited to 1815baa73d9eSNicolas Pitre CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1816baa73d9eSNicolas Pitre 1817baa73d9eSNicolas Pitre If unsure say y. 1818baa73d9eSNicolas Pitre 1819d59745ceSMatt Mackallconfig PRINTK 1820d59745ceSMatt Mackall default y 18216a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 182274876a98SFrederic Weisbecker select IRQ_WORK 1823d59745ceSMatt Mackall help 1824d59745ceSMatt Mackall This option enables normal printk support. Removing it 1825d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1826d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1827d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1828d59745ceSMatt Mackall strongly discouraged. 1829d59745ceSMatt Mackall 18305ea2bcdfSThomas Weißschuhconfig PRINTK_RINGBUFFER_KUNIT_TEST 18315ea2bcdfSThomas Weißschuh tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 18325ea2bcdfSThomas Weißschuh depends on PRINTK && KUNIT 18335ea2bcdfSThomas Weißschuh default KUNIT_ALL_TESTS 18345ea2bcdfSThomas Weißschuh help 18355ea2bcdfSThomas Weißschuh This builds the printk ringbuffer KUnit test suite. 18365ea2bcdfSThomas Weißschuh 18375ea2bcdfSThomas Weißschuh For more information on KUnit and unit tests in general, please refer 18385ea2bcdfSThomas Weißschuh to the KUnit documentation. 18395ea2bcdfSThomas Weißschuh 18405ea2bcdfSThomas Weißschuh If unsure, say N. 18415ea2bcdfSThomas Weißschuh 1842c8538a7aSMatt Mackallconfig BUG 18436a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1844c8538a7aSMatt Mackall default y 1845c8538a7aSMatt Mackall help 1846c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1847c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1848c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1849c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1850c8538a7aSMatt Mackall Just say Y. 1851c8538a7aSMatt Mackall 1852708e9a79SMatt Mackallconfig ELF_CORE 1853046d662fSAlex Kelly depends on COREDUMP 1854708e9a79SMatt Mackall default y 18556a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1856708e9a79SMatt Mackall help 1857708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1858708e9a79SMatt Mackall 18598761f1abSRalf Baechle 1860e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 18616a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 18628761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 186315f304b6SRalf Baechle select I8253_LOCK 1864e5e1d3cbSStas Sergeev default y 1865e5e1d3cbSStas Sergeev help 1866e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1867e5e1d3cbSStas Sergeev support, saving some memory. 1868e5e1d3cbSStas Sergeev 186927021649SYoann Congalconfig BASE_SMALL 187027021649SYoann Congal bool "Enable smaller-sized data structures for core" if EXPERT 18711da177e4SLinus Torvalds help 187227021649SYoann Congal Enabling this option reduces the size of miscellaneous core 18731da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 18741da177e4SLinus Torvalds but may reduce performance. 18751da177e4SLinus Torvalds 18761da177e4SLinus Torvaldsconfig FUTEX 18776a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 18783f2bedabSArnd Bergmann depends on !(SPARC32 && SMP) 18791da177e4SLinus Torvalds default y 1880bc2eecd7SNicolas Pitre imply RT_MUTEXES 18811da177e4SLinus Torvalds help 18821da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18831da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 18841da177e4SLinus Torvalds run glibc-based applications correctly. 18851da177e4SLinus Torvalds 1886bc2eecd7SNicolas Pitreconfig FUTEX_PI 1887bc2eecd7SNicolas Pitre bool 1888bc2eecd7SNicolas Pitre depends on FUTEX && RT_MUTEXES 1889bc2eecd7SNicolas Pitre default y 1890bc2eecd7SNicolas Pitre 189180367ad0SSebastian Andrzej Siewiorconfig FUTEX_PRIVATE_HASH 189280367ad0SSebastian Andrzej Siewior bool 189380367ad0SSebastian Andrzej Siewior depends on FUTEX && !BASE_SMALL && MMU 189480367ad0SSebastian Andrzej Siewior default y 189580367ad0SSebastian Andrzej Siewior 1896c042c505SPeter Zijlstraconfig FUTEX_MPOL 1897c042c505SPeter Zijlstra bool 1898c042c505SPeter Zijlstra depends on FUTEX && NUMA 1899c042c505SPeter Zijlstra default y 1900c042c505SPeter Zijlstra 1901042df0c1SThomas Gleixnerconfig HAVE_FUTEX_ROBUST_UNLOCK 1902042df0c1SThomas Gleixner bool 1903042df0c1SThomas Gleixner 1904042df0c1SThomas Gleixnerconfig FUTEX_ROBUST_UNLOCK 19052558084dSThomas Weißschuh def_bool FUTEX && GENERIC_IRQ_ENTRY && RSEQ && HAVE_FUTEX_ROBUST_UNLOCK 1906042df0c1SThomas Gleixner 19071da177e4SLinus Torvaldsconfig EPOLL 19086a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 19091da177e4SLinus Torvalds default y 19101da177e4SLinus Torvalds help 19111da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 19121da177e4SLinus Torvalds support for epoll family of system calls. 19131da177e4SLinus Torvalds 1914fba2afaaSDavide Libenziconfig SIGNALFD 19156a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1916fba2afaaSDavide Libenzi default y 1917fba2afaaSDavide Libenzi help 1918fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1919fba2afaaSDavide Libenzi on a file descriptor. 1920fba2afaaSDavide Libenzi 1921fba2afaaSDavide Libenzi If unsure, say Y. 1922fba2afaaSDavide Libenzi 1923b215e283SDavide Libenziconfig TIMERFD 19246a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1925b215e283SDavide Libenzi default y 1926b215e283SDavide Libenzi help 1927b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1928b215e283SDavide Libenzi events on a file descriptor. 1929b215e283SDavide Libenzi 1930b215e283SDavide Libenzi If unsure, say Y. 1931b215e283SDavide Libenzi 1932e1ad7468SDavide Libenziconfig EVENTFD 19336a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1934e1ad7468SDavide Libenzi default y 1935e1ad7468SDavide Libenzi help 1936e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1937e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1938e1ad7468SDavide Libenzi 1939e1ad7468SDavide Libenzi If unsure, say Y. 1940e1ad7468SDavide Libenzi 19411da177e4SLinus Torvaldsconfig SHMEM 19426a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 19431da177e4SLinus Torvalds default y 19441da177e4SLinus Torvalds depends on MMU 19451da177e4SLinus Torvalds help 19461da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 19471da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 19481da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 19491da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 19501da177e4SLinus Torvalds which may be appropriate on small systems without swap. 19511da177e4SLinus Torvalds 1952ebf3f09cSThomas Petazzoniconfig AIO 19536a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1954ebf3f09cSThomas Petazzoni default y 1955ebf3f09cSThomas Petazzoni help 1956ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1957ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1958ebf3f09cSThomas Petazzoni this option saves about 7k. 1959ebf3f09cSThomas Petazzoni 19602b188cc1SJens Axboeconfig IO_URING 19612b188cc1SJens Axboe bool "Enable IO uring support" if EXPERT 1962561fb04aSJens Axboe select IO_WQ 19632b188cc1SJens Axboe default y 19642b188cc1SJens Axboe help 19652b188cc1SJens Axboe This option enables support for the io_uring interface, enabling 19662b188cc1SJens Axboe applications to submit and complete IO through submission and 19672b188cc1SJens Axboe completion rings that are shared between the kernel and application. 19682b188cc1SJens Axboe 19691802656eSJens Axboeconfig GCOV_PROFILE_URING 19701802656eSJens Axboe bool "Enable GCOV profiling on the io_uring subsystem" 1971d1fbe1ebSRandy Dunlap depends on IO_URING && GCOV_KERNEL 19721802656eSJens Axboe help 19731802656eSJens Axboe Enable GCOV profiling on the io_uring subsystem, to facilitate 19741802656eSJens Axboe code coverage testing. 19751802656eSJens Axboe 19761802656eSJens Axboe If unsure, say N. 19771802656eSJens Axboe 19781802656eSJens Axboe Note that this will have a negative impact on the performance of 19791802656eSJens Axboe the io_uring subsystem, hence this should only be enabled for 19801802656eSJens Axboe specific test purposes. 19811802656eSJens Axboe 19823a0ae385SPavel Begunkovconfig IO_URING_MOCK_FILE 19833a0ae385SPavel Begunkov tristate "Enable io_uring mock files (Experimental)" if EXPERT 19843a0ae385SPavel Begunkov default n 19853a0ae385SPavel Begunkov depends on IO_URING 19863a0ae385SPavel Begunkov help 19879e7dc228SJ. Neuschäfer Enable mock files for io_uring subsystem testing. The ABI might 19883a0ae385SPavel Begunkov still change, so it's still experimental and should only be enabled 19893a0ae385SPavel Begunkov for specific test purposes. 19903a0ae385SPavel Begunkov 19913a0ae385SPavel Begunkov If unsure, say N. 19923a0ae385SPavel Begunkov 1993d3ac21caSJosh Triplettconfig ADVISE_SYSCALLS 1994d3ac21caSJosh Triplett bool "Enable madvise/fadvise syscalls" if EXPERT 1995d3ac21caSJosh Triplett default y 1996d3ac21caSJosh Triplett help 1997d3ac21caSJosh Triplett This option enables the madvise and fadvise syscalls, used by 1998d3ac21caSJosh Triplett applications to advise the kernel about their future memory or file 1999d3ac21caSJosh Triplett usage, improving performance. If building an embedded system where no 2000d3ac21caSJosh Triplett applications use these syscalls, you can disable this option to save 2001d3ac21caSJosh Triplett space. 2002d3ac21caSJosh Triplett 20035b25b13aSMathieu Desnoyersconfig MEMBARRIER 20045b25b13aSMathieu Desnoyers bool "Enable membarrier() system call" if EXPERT 20055b25b13aSMathieu Desnoyers default y 20065b25b13aSMathieu Desnoyers help 20075b25b13aSMathieu Desnoyers Enable the membarrier() system call that allows issuing memory 20085b25b13aSMathieu Desnoyers barriers across all running threads, which can be used to distribute 20095b25b13aSMathieu Desnoyers the cost of user-space memory barriers asymmetrically by transforming 20105b25b13aSMathieu Desnoyers pairs of memory barriers into pairs consisting of membarrier() and a 20115b25b13aSMathieu Desnoyers compiler barrier. 20125b25b13aSMathieu Desnoyers 20135b25b13aSMathieu Desnoyers If unsure, say Y. 20145b25b13aSMathieu Desnoyers 2015a751ea34SRandy Dunlapconfig KCMP 2016a751ea34SRandy Dunlap bool "Enable kcmp() system call" if EXPERT 2017a751ea34SRandy Dunlap help 2018a751ea34SRandy Dunlap Enable the kernel resource comparison system call. It provides 2019a751ea34SRandy Dunlap user-space with the ability to compare two processes to see if they 2020a751ea34SRandy Dunlap share a common resource, such as a file descriptor or even virtual 2021a751ea34SRandy Dunlap memory space. 2022a751ea34SRandy Dunlap 2023a751ea34SRandy Dunlap If unsure, say N. 2024a751ea34SRandy Dunlap 2025a751ea34SRandy Dunlapconfig RSEQ 2026a751ea34SRandy Dunlap bool "Enable rseq() system call" if EXPERT 2027a751ea34SRandy Dunlap default y 2028a751ea34SRandy Dunlap depends on HAVE_RSEQ 2029a751ea34SRandy Dunlap select MEMBARRIER 2030a751ea34SRandy Dunlap help 2031a751ea34SRandy Dunlap Enable the restartable sequences system call. It provides a 2032a751ea34SRandy Dunlap user-space cache for the current CPU number value, which 2033a751ea34SRandy Dunlap speeds up getting the current CPU number from user-space, 2034a751ea34SRandy Dunlap as well as an ABI to speed up user-space operations on 2035a751ea34SRandy Dunlap per-CPU data. 2036a751ea34SRandy Dunlap 2037a751ea34SRandy Dunlap If unsure, say Y. 2038a751ea34SRandy Dunlap 2039d7a5da7aSThomas Gleixnerconfig RSEQ_SLICE_EXTENSION 2040d7a5da7aSThomas Gleixner bool "Enable rseq-based time slice extension mechanism" 2041d7a5da7aSThomas Gleixner depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 2042d7a5da7aSThomas Gleixner help 2043d7a5da7aSThomas Gleixner Allows userspace to request a limited time slice extension when 2044d7a5da7aSThomas Gleixner returning from an interrupt to user space via the RSEQ shared 2045d7a5da7aSThomas Gleixner data ABI. If granted, that allows to complete a critical section, 2046d7a5da7aSThomas Gleixner so that other threads are not stuck on a conflicted resource, 2047d7a5da7aSThomas Gleixner while the task is scheduled out. 2048d7a5da7aSThomas Gleixner 2049d7a5da7aSThomas Gleixner If unsure, say N. 2050d7a5da7aSThomas Gleixner 205154129104SThomas Gleixnerconfig RSEQ_STATS 205254129104SThomas Gleixner default n 205354129104SThomas Gleixner bool "Enable lightweight statistics of restartable sequences" if EXPERT 205454129104SThomas Gleixner depends on RSEQ && DEBUG_FS 205554129104SThomas Gleixner help 205654129104SThomas Gleixner Enable lightweight counters which expose information about the 205754129104SThomas Gleixner frequency of RSEQ operations via debugfs. Mostly interesting for 205854129104SThomas Gleixner kernel debugging or performance analysis. While lightweight it's 205954129104SThomas Gleixner still adding code into the user/kernel mode transitions. 206054129104SThomas Gleixner 206154129104SThomas Gleixner If unsure, say N. 206254129104SThomas Gleixner 20639c37cb6eSThomas Gleixnerconfig RSEQ_DEBUG_DEFAULT_ENABLE 20649c37cb6eSThomas Gleixner default n 20659c37cb6eSThomas Gleixner bool "Enable restartable sequences debug mode by default" if EXPERT 20669c37cb6eSThomas Gleixner depends on RSEQ 20679c37cb6eSThomas Gleixner help 20689c37cb6eSThomas Gleixner This enables the static branch for debug mode of restartable 20699c37cb6eSThomas Gleixner sequences. 20709c37cb6eSThomas Gleixner 20719c37cb6eSThomas Gleixner This also can be controlled on the kernel command line via the 20729c37cb6eSThomas Gleixner command line parameter "rseq_debug=0/1" and through debugfs. 20739c37cb6eSThomas Gleixner 20749c37cb6eSThomas Gleixner If unsure, say N. 20759c37cb6eSThomas Gleixner 2076a751ea34SRandy Dunlapconfig DEBUG_RSEQ 2077a751ea34SRandy Dunlap default n 2078a751ea34SRandy Dunlap bool "Enable debugging of rseq() system call" if EXPERT 20793db6b38dSThomas Gleixner depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 20809c37cb6eSThomas Gleixner select RSEQ_DEBUG_DEFAULT_ENABLE 2081a751ea34SRandy Dunlap help 2082a751ea34SRandy Dunlap Enable extra debugging checks for the rseq system call. 2083a751ea34SRandy Dunlap 2084a751ea34SRandy Dunlap If unsure, say N. 2085a751ea34SRandy Dunlap 2086a751ea34SRandy Dunlapconfig CACHESTAT_SYSCALL 2087a751ea34SRandy Dunlap bool "Enable cachestat() system call" if EXPERT 2088a751ea34SRandy Dunlap default y 2089a751ea34SRandy Dunlap help 2090a751ea34SRandy Dunlap Enable the cachestat system call, which queries the page cache 2091a751ea34SRandy Dunlap statistics of a file (number of cached pages, dirty pages, 2092a751ea34SRandy Dunlap pages marked for writeback, (recently) evicted pages). 2093a751ea34SRandy Dunlap 2094a751ea34SRandy Dunlap If unsure say Y here. 2095a751ea34SRandy Dunlap 2096d1b069f5SRandy Dunlapconfig KALLSYMS 2097d1b069f5SRandy Dunlap bool "Load all symbols for debugging/ksymoops" if EXPERT 2098d1b069f5SRandy Dunlap default y 2099d1b069f5SRandy Dunlap help 2100d1b069f5SRandy Dunlap Say Y here to let the kernel print out symbolic crash information and 2101d1b069f5SRandy Dunlap symbolic stack backtraces. This increases the size of the kernel 2102d1b069f5SRandy Dunlap somewhat, as all symbols have to be loaded into the kernel image. 2103d1b069f5SRandy Dunlap 210430f3bb09SZhen Leiconfig KALLSYMS_SELFTEST 210530f3bb09SZhen Lei bool "Test the basic functions and performance of kallsyms" 210630f3bb09SZhen Lei depends on KALLSYMS 210730f3bb09SZhen Lei default n 210830f3bb09SZhen Lei help 210930f3bb09SZhen Lei Test the basic functions and performance of some interfaces, such as 211030f3bb09SZhen Lei kallsyms_lookup_name. It also calculates the compression rate of the 211130f3bb09SZhen Lei kallsyms compression algorithm for the current symbol set. 211230f3bb09SZhen Lei 211330f3bb09SZhen Lei Start self-test automatically after system startup. Suggest executing 211430f3bb09SZhen Lei "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 211530f3bb09SZhen Lei displayed in the last line, indicating that the test is complete. 211630f3bb09SZhen Lei 2117d1b069f5SRandy Dunlapconfig KALLSYMS_ALL 2118d1b069f5SRandy Dunlap bool "Include all symbols in kallsyms" 2119d1b069f5SRandy Dunlap depends on DEBUG_KERNEL && KALLSYMS 2120d1b069f5SRandy Dunlap help 2121d1b069f5SRandy Dunlap Normally kallsyms only contains the symbols of functions for nicer 2122d1b069f5SRandy Dunlap OOPS messages and backtraces (i.e., symbols from the text and inittext 2123bdf0fe33SBaruch Siach sections). This is sufficient for most cases. And only if you want to 2124bdf0fe33SBaruch Siach enable kernel live patching, or other less common use cases (e.g., 2125bdf0fe33SBaruch Siach when a debugger is used) all symbols are required (i.e., names of 2126bdf0fe33SBaruch Siach variables from the data sections, etc). 2127d1b069f5SRandy Dunlap 2128d1b069f5SRandy Dunlap This option makes sure that all symbols are loaded into the kernel 2129d1b069f5SRandy Dunlap image (i.e., symbols from all sections) in cost of increased kernel 2130d1b069f5SRandy Dunlap size (depending on the kernel configuration, it may be 300KiB or 2131d1b069f5SRandy Dunlap something like this). 2132d1b069f5SRandy Dunlap 2133bdf0fe33SBaruch Siach Say N unless you really need all symbols, or kernel live patching. 2134d1b069f5SRandy Dunlap 2135d1b069f5SRandy Dunlap# end of the "standard kernel features (expert users)" menu 2136d1b069f5SRandy Dunlap 21373ccfebedSMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_CALLBACKS 21383ccfebedSMathieu Desnoyers bool 21393ccfebedSMathieu Desnoyers 214070216e18SMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_SYNC_CORE 214170216e18SMathieu Desnoyers bool 214270216e18SMathieu Desnoyers 21435796d396SJeff Xuconfig ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 21445796d396SJeff Xu bool 21455796d396SJeff Xu help 21465796d396SJeff Xu Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 21475796d396SJeff Xu 21485796d396SJeff Xu A 64-bit kernel is required for the memory sealing feature. 21495796d396SJeff Xu No specific hardware features from the CPU are needed. 21505796d396SJeff Xu 21515796d396SJeff Xu To enable this feature, the architecture needs to update their 21525796d396SJeff Xu special mappings calls to include the sealing flag and confirm 21535796d396SJeff Xu that it doesn't unmap/remap system mappings during the life 21545796d396SJeff Xu time of the process. The existence of this flag for an architecture 21555796d396SJeff Xu implies that it does not require the remapping of the system 21565796d396SJeff Xu mappings during process lifetime, so sealing these mappings is safe 21575796d396SJeff Xu from a kernel perspective. 21585796d396SJeff Xu 21595796d396SJeff Xu After the architecture enables this, a distribution can set 2160e474ac24SLeon Hwang CONFIG_MSEAL_SYSTEM_MAPPINGS to manage access to the feature. 21615796d396SJeff Xu 21625796d396SJeff Xu For complete descriptions of memory sealing, please see 21635796d396SJeff Xu Documentation/userspace-api/mseal.rst 21645796d396SJeff Xu 2165cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 21660793a61dSThomas Gleixner bool 2167018df72dSMike Frysinger help 2168018df72dSMike Frysinger See tools/perf/design.txt for details. 21690793a61dSThomas Gleixner 21702aef6f30SSean Christophersonconfig GUEST_PERF_EVENTS 21712aef6f30SSean Christopherson bool 21722aef6f30SSean Christopherson depends on HAVE_PERF_EVENTS 21732aef6f30SSean Christopherson 2174eff95e17SKan Liangconfig PERF_GUEST_MEDIATED_PMU 2175eff95e17SKan Liang bool 2176eff95e17SKan Liang depends on GUEST_PERF_EVENTS 2177eff95e17SKan Liang 2178906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 2179906010b2SPeter Zijlstra bool 2180906010b2SPeter Zijlstra help 2181906010b2SPeter Zijlstra See tools/perf/design.txt for details 2182906010b2SPeter Zijlstra 218357c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 21840793a61dSThomas Gleixner 2185cdd6c482SIngo Molnarconfig PERF_EVENTS 218657c0c15bSIngo Molnar bool "Kernel performance events and counters" 2187392d65a9SRobert Richter default y if PROFILING 2188cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 2189e360adbeSPeter Zijlstra select IRQ_WORK 21900793a61dSThomas Gleixner help 219157c0c15bSIngo Molnar Enable kernel support for various performance events provided 219257c0c15bSIngo Molnar by software and hardware. 21930793a61dSThomas Gleixner 2194dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 219557c0c15bSIngo Molnar use of generic tracepoints. 219657c0c15bSIngo Molnar 219757c0c15bSIngo Molnar Most modern CPUs support performance events via performance 219857c0c15bSIngo Molnar counter registers. These registers count the number of certain 21990793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 22000793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 22010793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 22020793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 22030793a61dSThomas Gleixner used to profile the code that runs on that CPU. 22040793a61dSThomas Gleixner 220557c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 2206dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 220757c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 22080793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 22090793a61dSThomas Gleixner capabilities on top of those. 22100793a61dSThomas Gleixner 22110793a61dSThomas Gleixner Say Y if unsure. 22120793a61dSThomas Gleixner 2213906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 2214906010b2SPeter Zijlstra default n 2215906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 2216cb307113SMichael Ellerman depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2217906010b2SPeter Zijlstra select PERF_USE_VMALLOC 2218906010b2SPeter Zijlstra help 2219906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 2220906010b2SPeter Zijlstra 2221906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 2222906010b2SPeter Zijlstra that don't require it. 2223906010b2SPeter Zijlstra 2224906010b2SPeter Zijlstra Say N if unsure. 2225906010b2SPeter Zijlstra 22260793a61dSThomas Gleixnerendmenu 22270793a61dSThomas Gleixner 2228091f6e26SDavid Howellsconfig SYSTEM_DATA_VERIFICATION 2229091f6e26SDavid Howells def_bool n 2230091f6e26SDavid Howells select SYSTEM_TRUSTED_KEYRING 2231091f6e26SDavid Howells select KEYS 2232091f6e26SDavid Howells select CRYPTO 2233d43de6c7SDavid Howells select CRYPTO_RSA 2234091f6e26SDavid Howells select ASYMMETRIC_KEY_TYPE 2235091f6e26SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2236091f6e26SDavid Howells select ASN1 2237091f6e26SDavid Howells select OID_REGISTRY 2238091f6e26SDavid Howells select X509_CERTIFICATE_PARSER 2239091f6e26SDavid Howells select PKCS7_MESSAGE_PARSER 224082c04ff8SPeter Foley help 2241091f6e26SDavid Howells Provide PKCS#7 message verification using the contents of the system 2242091f6e26SDavid Howells trusted keyring to provide public keys. This then can be used for 2243091f6e26SDavid Howells module verification, kexec image verification and firmware blob 2244091f6e26SDavid Howells verification. 224582c04ff8SPeter Foley 2246125e5645SMathieu Desnoyersconfig PROFILING 2247b309a294SRobert Richter bool "Profiling support" 2248125e5645SMathieu Desnoyers help 2249125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 2250f8408264SViresh Kumar by profilers. 2251125e5645SMathieu Desnoyers 22522f7ab126SMiguel Ojedaconfig RUST 22532f7ab126SMiguel Ojeda bool "Rust support" 22542f7ab126SMiguel Ojeda depends on HAVE_RUST 22552f7ab126SMiguel Ojeda depends on RUST_IS_AVAILABLE 2256ac61506bSSami Tolvanen select EXTENDED_MODVERSIONS if MODVERSIONS 2257ac61506bSSami Tolvanen depends on !MODVERSIONS || GENDWARFKSYMS 2258f1385dc6SNeal Gompa depends on !GCC_PLUGIN_RANDSTRUCT 22592f7ab126SMiguel Ojeda depends on !RANDSTRUCT 22605daa0c35SMatthew Maurer depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 226123ef9d43SKees Cook depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 226223ef9d43SKees Cook select CFI_ICALL_NORMALIZE_INTEGERS if CFI 22635b271543SAlice Ryhl depends on !KASAN || CC_IS_CLANG 226472d33b8bSAlice Ryhl depends on !KASAN_SW_TAGS || RUSTC_VERSION >= 109600 22652f7ab126SMiguel Ojeda help 22662f7ab126SMiguel Ojeda Enables Rust support in the kernel. 22672f7ab126SMiguel Ojeda 22682f7ab126SMiguel Ojeda This allows other Rust-related options, like drivers written in Rust, 22692f7ab126SMiguel Ojeda to be selected. 22702f7ab126SMiguel Ojeda 22712f7ab126SMiguel Ojeda It is also required to be able to load external kernel modules 22722f7ab126SMiguel Ojeda written in Rust. 22732f7ab126SMiguel Ojeda 22742f7ab126SMiguel Ojeda See Documentation/rust/ for more information. 22752f7ab126SMiguel Ojeda 22762f7ab126SMiguel Ojeda If unsure, say N. 22772f7ab126SMiguel Ojeda 2278e74b7a3fSYury Norovsource "rust/kernel/Kconfig.test" 2279e74b7a3fSYury Norov 22802f7ab126SMiguel Ojedaconfig RUSTC_VERSION_TEXT 22812f7ab126SMiguel Ojeda string 22822f7ab126SMiguel Ojeda depends on RUST 22835134a335SMiguel Ojeda default "$(RUSTC_VERSION_TEXT)" 22845134a335SMiguel Ojeda help 22855134a335SMiguel Ojeda See `CC_VERSION_TEXT`. 22862f7ab126SMiguel Ojeda 22872f7ab126SMiguel Ojedaconfig BINDGEN_VERSION_TEXT 22882f7ab126SMiguel Ojeda string 22892f7ab126SMiguel Ojeda depends on RUST 229093553d99SMiguel Ojeda default "$(shell,$(BINDGEN) --version 2>/dev/null)" 22912f7ab126SMiguel Ojeda 22925f87f112SIngo Molnar# 22935f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 22945f87f112SIngo Molnar# dynamically changed for a probe function. 22955f87f112SIngo Molnar# 229697e1c18eSMathieu Desnoyersconfig TRACEPOINTS 22975f87f112SIngo Molnar bool 2298a363d27cSMathieu Desnoyers select TASKS_TRACE_RCU 229997e1c18eSMathieu Desnoyers 230089cde455SEric DeVoldersource "kernel/Kconfig.kexec" 230189cde455SEric DeVolder 230248a1b232SPasha Tatashinsource "kernel/liveupdate/Kconfig" 230348a1b232SPasha Tatashin 23041da177e4SLinus Torvaldsendmenu # General setup 23051da177e4SLinus Torvalds 23061572497cSChristoph Hellwigsource "arch/Kconfig" 23071572497cSChristoph Hellwig 2308ae81f9e3SChuck Ebbertconfig RT_MUTEXES 23096341e62bSChristoph Jaeger bool 23101c6f9ec0SSebastian Andrzej Siewior default y if PREEMPT_RT 2311ae81f9e3SChuck Ebbert 2312c8424e77SThiago Jung Bauermannconfig MODULE_SIG_FORMAT 2313c8424e77SThiago Jung Bauermann def_bool n 2314c8424e77SThiago Jung Bauermann select SYSTEM_DATA_VERIFICATION 2315c8424e77SThiago Jung Bauermann 231673b4fc92SChristophe Leroysource "kernel/module/Kconfig" 23176c9692e2SPeter Zijlstra 231898a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 231998a79d6aSRusty Russell bool 232098a79d6aSRusty Russell help 23215f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 23225f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 232398a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 232498a79d6aSRusty Russell it was better to provide this option than to break all the archs 2325692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 232698a79d6aSRusty Russell 23273a65dfe8SJens Axboesource "block/Kconfig" 2328e98c3202SAvi Kivity 2329e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 2330e98c3202SAvi Kivity bool 2331e260be67SPaul E. McKenney 233216295becSSteffen Klassertconfig PADATA 233316295becSSteffen Klassert depends on SMP 233416295becSSteffen Klassert bool 233516295becSSteffen Klassert 23364520c6a4SDavid Howellsconfig ASN1 23374520c6a4SDavid Howells tristate 23384520c6a4SDavid Howells help 23394520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 23404520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 23414520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 23424520c6a4SDavid Howells functions to call on what tags. 23434520c6a4SDavid Howells 23446beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 2345e61938a9SMathieu Desnoyers 23460ebeea8cSDaniel Borkmannconfig ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 23470ebeea8cSDaniel Borkmann bool 23480ebeea8cSDaniel Borkmann 23494ff4c745SAndrea Parriconfig ARCH_HAS_PREPARE_SYNC_CORE_CMD 23504ff4c745SAndrea Parri bool 23514ff4c745SAndrea Parri 2352e61938a9SMathieu Desnoyersconfig ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2353e61938a9SMathieu Desnoyers bool 23541bd21c6cSDominik Brodowski 23551bd21c6cSDominik Brodowski# It may be useful for an architecture to override the definitions of the 23567303e30eSDominik Brodowski# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 23577303e30eSDominik Brodowski# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 23587303e30eSDominik Brodowski# different calling convention for syscalls. They can also override the 23597303e30eSDominik Brodowski# macros for not-implemented syscalls in kernel/sys_ni.c and 23607303e30eSDominik Brodowski# kernel/time/posix-stubs.c. All these overrides need to be available in 23617303e30eSDominik Brodowski# <asm/syscall_wrapper.h>. 23621bd21c6cSDominik Brodowskiconfig ARCH_HAS_SYSCALL_WRAPPER 23631bd21c6cSDominik Brodowski def_bool n 2364