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) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 175b688f369SKees Cook 176e7607f7dSNathan Chancellorconfig LD_CAN_USE_KEEP_IN_OVERLAY 177e7607f7dSNathan Chancellor # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 178e7607f7dSNathan Chancellor # https://github.com/llvm/llvm-project/pull/130661 179e7607f7dSNathan Chancellor def_bool LD_IS_BFD || LLD_VERSION >= 210000 180e7607f7dSNathan Chancellor 18136174d16SMiguel Ojedaconfig RUSTC_HAS_SPAN_FILE 18236174d16SMiguel Ojeda def_bool RUSTC_VERSION >= 108800 18336174d16SMiguel Ojeda 1847129ea6eSMiguel Ojedaconfig RUSTC_HAS_UNNECESSARY_TRANSMUTES 1857129ea6eSMiguel Ojeda def_bool RUSTC_VERSION >= 108800 1867129ea6eSMiguel Ojeda 1870aa2b78cSBoqun Fengconfig RUSTC_HAS_FILE_WITH_NUL 1880aa2b78cSBoqun Feng def_bool RUSTC_VERSION >= 108900 1890aa2b78cSBoqun Feng 190c09461a0SAlice Ryhlconfig RUSTC_HAS_FILE_AS_C_STR 191c09461a0SAlice Ryhl def_bool RUSTC_VERSION >= 109100 192c09461a0SAlice Ryhl 193613fe169SNathan Chancellorconfig PAHOLE_VERSION 194613fe169SNathan Chancellor int 19590e5b38aSIhor Solodrai default "$(PAHOLE_VERSION)" 196613fe169SNathan Chancellor 197b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 198b99b87f7SPeter Oberparleiter bool 199b99b87f7SPeter Oberparleiter 200e360adbeSPeter Zijlstraconfig IRQ_WORK 201fd0a68a2STejun Heo def_bool y if SMP 202e360adbeSPeter Zijlstra 20310916706SShile Zhangconfig BUILDTIME_TABLE_SORT 2041dbdc6f1SDavid Daney bool 2051dbdc6f1SDavid Daney 206c65eacbeSAndy Lutomirskiconfig THREAD_INFO_IN_TASK 207c65eacbeSAndy Lutomirski bool 208c65eacbeSAndy Lutomirski help 209c65eacbeSAndy Lutomirski Select this to move thread_info off the stack into task_struct. To 210c65eacbeSAndy Lutomirski make this work, an arch will need to remove all thread_info fields 211c65eacbeSAndy Lutomirski except flags and fix any runtime bugs. 212c65eacbeSAndy Lutomirski 213c6c314a6SAndy Lutomirski One subtle change that will be needed is to use try_get_task_stack() 214c6c314a6SAndy Lutomirski and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 215c6c314a6SAndy Lutomirski 216ff0cfc66SAl Boldimenu "General setup" 2171da177e4SLinus Torvalds 2181da177e4SLinus Torvaldsconfig BROKEN 2191da177e4SLinus Torvalds bool 220fefbeed8SAndrew Morton help 221fefbeed8SAndrew Morton This option allows you to choose whether you want to try to 222fefbeed8SAndrew Morton compile (and fix) old drivers that haven't been updated to 223fefbeed8SAndrew Morton new infrastructure. 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 2261da177e4SLinus Torvalds bool 2271da177e4SLinus Torvalds depends on BROKEN || !SMP 2281da177e4SLinus Torvalds default y 2291da177e4SLinus Torvalds 2301da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 2311da177e4SLinus Torvalds int 232dd673bcaSAdrian Bunk default 32 if !UML 233dd673bcaSAdrian Bunk default 128 if UML 2341da177e4SLinus Torvalds help 23534ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 23634ad92c2SRandy Dunlap variables passed to init from the kernel command line. 2371da177e4SLinus Torvalds 2384bb16672SJiri Slabyconfig COMPILE_TEST 2394bb16672SJiri Slaby bool "Compile also drivers which will not load" 240ea29b20aSMasahiro Yamada depends on HAS_IOMEM 2414bb16672SJiri Slaby help 2424bb16672SJiri Slaby Some drivers can be compiled on a different platform than they are 2434bb16672SJiri Slaby intended to be run on. Despite they cannot be loaded there (or even 2444bb16672SJiri Slaby when they load they cannot be used due to missing HW support), 2454bb16672SJiri Slaby developers still, opposing to distributors, might want to build such 2464bb16672SJiri Slaby drivers to compile-test them. 2474bb16672SJiri Slaby 2484bb16672SJiri Slaby If you are a developer and want to build everything available, say Y 2494bb16672SJiri Slaby here. If you are a user/distributor, say N here to exclude useless 2504bb16672SJiri Slaby drivers to be distributed. 2514bb16672SJiri Slaby 2523fe617ccSLinus Torvaldsconfig WERROR 2533fe617ccSLinus Torvalds bool "Compile the kernel with warnings as errors" 254b339ec9cSMarco Elver default COMPILE_TEST 2553fe617ccSLinus Torvalds help 2563fe617ccSLinus Torvalds A kernel build should not cause any compiler warnings, and this 2572f7ab126SMiguel Ojeda enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 258e1789d7cSXin Li to enforce that rule by default. Certain warnings from other tools 259e1789d7cSXin Li such as the linker may be upgraded to errors with this option as 260e1789d7cSXin Li well. 2613fe617ccSLinus Torvalds 262e1789d7cSXin Li However, if you have a new (or very old) compiler or linker with odd 263e1789d7cSXin Li and unusual warnings, or you have some architecture with problems, 2643fe617ccSLinus Torvalds you may need to disable this config option in order to 2653fe617ccSLinus Torvalds successfully build the kernel. 2663fe617ccSLinus Torvalds 2673fe617ccSLinus Torvalds If in doubt, say Y. 2683fe617ccSLinus Torvalds 269d6fc9fcbSMasahiro Yamadaconfig UAPI_HEADER_TEST 270d6fc9fcbSMasahiro Yamada bool "Compile test UAPI headers" 2712a0a3080SThomas Weißschuh depends on HEADERS_INSTALL 272d6fc9fcbSMasahiro Yamada help 273d6fc9fcbSMasahiro Yamada Compile test headers exported to user-space to ensure they are 274d6fc9fcbSMasahiro Yamada self-contained, i.e. compilable as standalone units. 275d6fc9fcbSMasahiro Yamada 276d6fc9fcbSMasahiro Yamada If you are a developer or tester and want to ensure the exported 277d6fc9fcbSMasahiro Yamada headers are self-contained, say Y here. Otherwise, choose N. 278d6fc9fcbSMasahiro Yamada 2791da177e4SLinus Torvaldsconfig LOCALVERSION 2801da177e4SLinus Torvalds string "Local version - append to kernel release" 2811da177e4SLinus Torvalds help 2821da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 2831da177e4SLinus Torvalds This will show up when you type uname, for example. 2841da177e4SLinus Torvalds The string you set here will be appended after the contents of 2851da177e4SLinus Torvalds any files with a filename matching localversion* in your 2861da177e4SLinus Torvalds object and source tree, in that order. Your total string can 2871da177e4SLinus Torvalds be a maximum of 64 characters. 2881da177e4SLinus Torvalds 289aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 290aaebf433SRyan Anderson bool "Automatically append version information to the version string" 291aaebf433SRyan Anderson default y 292ac3339baSAlexey Dobriyan depends on !COMPILE_TEST 293aaebf433SRyan Anderson help 294aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 2956e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 2966e5a5420SRobert P. J. Day top of tree revision. 297aaebf433SRyan Anderson 298aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 2996e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 300aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 3016e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 302aaebf433SRyan Anderson 3030f9c608dSRasmus Villemoes (The actual string used here is the first 12 characters produced 3046e5a5420SRobert P. J. Day by running the command: 3056e5a5420SRobert P. J. Day 3066e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 3076e5a5420SRobert P. J. Day 3086e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 309aaebf433SRyan Anderson 3109afb719eSLaura Abbottconfig BUILD_SALT 3119afb719eSLaura Abbott string "Build ID Salt" 3129afb719eSLaura Abbott default "" 3139afb719eSLaura Abbott help 3149afb719eSLaura Abbott The build ID is used to link binaries and their debug info. Setting 3159afb719eSLaura Abbott this option will use the value in the calculation of the build id. 3169afb719eSLaura Abbott This is mostly useful for distributions which want to ensure the 3179afb719eSLaura Abbott build is unique between builds. It's safe to leave the default. 3189afb719eSLaura Abbott 3192e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 3202e9f3bddSH. Peter Anvin bool 3212e9f3bddSH. Peter Anvin 3222e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 3232e9f3bddSH. Peter Anvin bool 3242e9f3bddSH. Peter Anvin 3252e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 3262e9f3bddSH. Peter Anvin bool 3272e9f3bddSH. Peter Anvin 3283ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 3293ebe1243SLasse Collin bool 3303ebe1243SLasse Collin 3317dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 3327dd65febSAlbin Tonnerre bool 3337dd65febSAlbin Tonnerre 334e76e1fdfSKyungsik Leeconfig HAVE_KERNEL_LZ4 335e76e1fdfSKyungsik Lee bool 336e76e1fdfSKyungsik Lee 33748f7ddf7SNick Terrellconfig HAVE_KERNEL_ZSTD 33848f7ddf7SNick Terrell bool 33948f7ddf7SNick Terrell 340f16466afSVasily Gorbikconfig HAVE_KERNEL_UNCOMPRESSED 341f16466afSVasily Gorbik bool 342f16466afSVasily Gorbik 34330d65dbfSAlain Knaffchoice 34430d65dbfSAlain Knaff prompt "Kernel compression mode" 34530d65dbfSAlain Knaff default KERNEL_GZIP 34648f7ddf7SNick 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 34730d65dbfSAlain Knaff help 34830d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 34930d65dbfSAlain Knaff Several compression algorithms are available, which differ 35030d65dbfSAlain Knaff in efficiency, compression and decompression speed. 35130d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 35230d65dbfSAlain Knaff Decompression speed is relevant at each boot. 35330d65dbfSAlain Knaff 35430d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 35530d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 35630d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 35730d65dbfSAlain Knaff supplied by Christian Ludwig) 35830d65dbfSAlain Knaff 35930d65dbfSAlain Knaff High compression options are mostly useful for users, who 36030d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 36130d65dbfSAlain Knaff size matters less. 36230d65dbfSAlain Knaff 36330d65dbfSAlain Knaff If in doubt, select 'gzip' 36430d65dbfSAlain Knaff 36530d65dbfSAlain Knaffconfig KERNEL_GZIP 36630d65dbfSAlain Knaff bool "Gzip" 3672e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 36830d65dbfSAlain Knaff help 3697dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 3707dd65febSAlbin Tonnerre between compression ratio and decompression speed. 37130d65dbfSAlain Knaff 37230d65dbfSAlain Knaffconfig KERNEL_BZIP2 37330d65dbfSAlain Knaff bool "Bzip2" 3742e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 37530d65dbfSAlain Knaff help 37630d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 3770a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 3782e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 3792e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 3802e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 38130d65dbfSAlain Knaff 38230d65dbfSAlain Knaffconfig KERNEL_LZMA 38330d65dbfSAlain Knaff bool "LZMA" 3842e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 38530d65dbfSAlain Knaff help 3860a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 3870a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 3880a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 38930d65dbfSAlain Knaff 3903ebe1243SLasse Collinconfig KERNEL_XZ 3913ebe1243SLasse Collin bool "XZ" 3923ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 3933ebe1243SLasse Collin help 3943ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 3953ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 3963ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 3973ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 3987472ff8aSLasse Collin filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 3997472ff8aSLasse Collin and SPARC), XZ will create a few percent smaller kernel than 4007472ff8aSLasse Collin plain LZMA. 4013ebe1243SLasse Collin 4023ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 4033ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 4043ebe1243SLasse Collin and LZO. Compression is slow. 4053ebe1243SLasse Collin 4067dd65febSAlbin Tonnerreconfig KERNEL_LZO 4077dd65febSAlbin Tonnerre bool "LZO" 4087dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 4097dd65febSAlbin Tonnerre help 4100a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 411681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 4127dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 4137dd65febSAlbin Tonnerre 414e76e1fdfSKyungsik Leeconfig KERNEL_LZ4 415e76e1fdfSKyungsik Lee bool "LZ4" 416e76e1fdfSKyungsik Lee depends on HAVE_KERNEL_LZ4 417e76e1fdfSKyungsik Lee help 418e76e1fdfSKyungsik Lee LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 419e76e1fdfSKyungsik Lee A preliminary version of LZ4 de/compression tool is available at 420e76e1fdfSKyungsik Lee <https://code.google.com/p/lz4/>. 421e76e1fdfSKyungsik Lee 422e76e1fdfSKyungsik Lee Its compression ratio is worse than LZO. The size of the kernel 423e76e1fdfSKyungsik Lee is about 8% bigger than LZO. But the decompression speed is 424e76e1fdfSKyungsik Lee faster than LZO. 425e76e1fdfSKyungsik Lee 42648f7ddf7SNick Terrellconfig KERNEL_ZSTD 42748f7ddf7SNick Terrell bool "ZSTD" 42848f7ddf7SNick Terrell depends on HAVE_KERNEL_ZSTD 42948f7ddf7SNick Terrell help 43048f7ddf7SNick Terrell ZSTD is a compression algorithm targeting intermediate compression 43148f7ddf7SNick Terrell with fast decompression speed. It will compress better than GZIP and 43248f7ddf7SNick Terrell decompress around the same speed as LZO, but slower than LZ4. You 43348f7ddf7SNick Terrell will need at least 192 KB RAM or more for booting. The zstd command 43448f7ddf7SNick Terrell line tool is required for compression. 43548f7ddf7SNick Terrell 436f16466afSVasily Gorbikconfig KERNEL_UNCOMPRESSED 437f16466afSVasily Gorbik bool "None" 438f16466afSVasily Gorbik depends on HAVE_KERNEL_UNCOMPRESSED 439f16466afSVasily Gorbik help 440f16466afSVasily Gorbik Produce uncompressed kernel image. This option is usually not what 441f16466afSVasily Gorbik you want. It is useful for debugging the kernel in slow simulation 442f16466afSVasily Gorbik environments, where decompressing and moving the kernel is awfully 443f16466afSVasily Gorbik slow. This option allows early boot code to skip the decompressor 444f16466afSVasily Gorbik and jump right at uncompressed kernel image. 445f16466afSVasily Gorbik 44630d65dbfSAlain Knaffendchoice 44730d65dbfSAlain Knaff 448ada4ab7aSChris Downconfig DEFAULT_INIT 449ada4ab7aSChris Down string "Default init path" 450ada4ab7aSChris Down default "" 451ada4ab7aSChris Down help 452ada4ab7aSChris Down This option determines the default init for the system if no init= 453ada4ab7aSChris Down option is passed on the kernel command line. If the requested path is 454ada4ab7aSChris Down not present, we will still then move on to attempting further 455ada4ab7aSChris Down locations (e.g. /sbin/init, etc). If this is empty, we will just use 456ada4ab7aSChris Down the fallback list when init= is not passed. 457ada4ab7aSChris Down 458bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 459bd5dc17bSJosh Triplett string "Default hostname" 460bd5dc17bSJosh Triplett default "(none)" 461bd5dc17bSJosh Triplett help 462bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 463bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 464bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 465bd5dc17bSJosh Triplett system more usable with less configuration. 466bd5dc17bSJosh Triplett 4671da177e4SLinus Torvaldsconfig SYSVIPC 4681da177e4SLinus Torvalds bool "System V IPC" 469a7f7f624SMasahiro Yamada help 4701da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 4711da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 4721da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 4731da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 4741da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 4751da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 4761da177e4SLinus Torvalds you'll need to say Y here. 4771da177e4SLinus Torvalds 4781da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 4791da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 4801da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 4811da177e4SLinus Torvalds 482a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 483a5494dcdSEric W. Biederman bool 484a5494dcdSEric W. Biederman depends on SYSVIPC 485a5494dcdSEric W. Biederman depends on SYSCTL 486a5494dcdSEric W. Biederman default y 487a5494dcdSEric W. Biederman 4880cbed0eeSGuo Renconfig SYSVIPC_COMPAT 4890cbed0eeSGuo Ren def_bool y 4900cbed0eeSGuo Ren depends on COMPAT && SYSVIPC 4910cbed0eeSGuo Ren 4921da177e4SLinus Torvaldsconfig POSIX_MQUEUE 4931da177e4SLinus Torvalds bool "POSIX Message Queues" 49419c92399SKees Cook depends on NET 495a7f7f624SMasahiro Yamada help 4961da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 4971da177e4SLinus Torvalds queues every message has a priority which decides about succession 4981da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 4991da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 500b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 5011da177e4SLinus Torvalds 5021da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 5031da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 5041da177e4SLinus Torvalds operations on message queues. 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds If unsure, say Y. 5071da177e4SLinus Torvalds 508bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 509bdc8e5f8SSerge E. Hallyn bool 510bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 511bdc8e5f8SSerge E. Hallyn depends on SYSCTL 512bdc8e5f8SSerge E. Hallyn default y 513bdc8e5f8SSerge E. Hallyn 514c73be61cSDavid Howellsconfig WATCH_QUEUE 515c73be61cSDavid Howells bool "General notification queue" 516c73be61cSDavid Howells default n 517c73be61cSDavid Howells help 518c73be61cSDavid Howells 519c73be61cSDavid Howells This is a general notification queue for the kernel to pass events to 520c73be61cSDavid Howells userspace by splicing them into pipes. It can be used in conjunction 521c73be61cSDavid Howells with watches for key/keyring change notifications and device 522c73be61cSDavid Howells notifications. 523c73be61cSDavid Howells 524c02b872aSMauro Carvalho Chehab See Documentation/core-api/watch_queue.rst 525c73be61cSDavid Howells 526226b4ccdSKonstantin Khlebnikovconfig CROSS_MEMORY_ATTACH 527226b4ccdSKonstantin Khlebnikov bool "Enable process_vm_readv/writev syscalls" 528226b4ccdSKonstantin Khlebnikov depends on MMU 529226b4ccdSKonstantin Khlebnikov default y 530226b4ccdSKonstantin Khlebnikov help 531226b4ccdSKonstantin Khlebnikov Enabling this option adds the system calls process_vm_readv and 532226b4ccdSKonstantin Khlebnikov process_vm_writev which allow a process with the correct privileges 533a2a368d9SGeert Uytterhoeven to directly read from or write to another process' address space. 534226b4ccdSKonstantin Khlebnikov See the man page for more details. 535226b4ccdSKonstantin Khlebnikov 5361da177e4SLinus Torvaldsconfig AUDIT 5371da177e4SLinus Torvalds bool "Auditing support" 538804a6a49SChris Wright depends on NET 5391da177e4SLinus Torvalds help 5401da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 5411da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 542cb74ed27SPaul Moore logging of avc messages output). System call auditing is included 543cb74ed27SPaul Moore on architectures which support it. 5441da177e4SLinus Torvalds 5457a017721SAKASHI Takahiroconfig HAVE_ARCH_AUDITSYSCALL 5467a017721SAKASHI Takahiro bool 5477a017721SAKASHI Takahiro 5481da177e4SLinus Torvaldsconfig AUDITSYSCALL 549cb74ed27SPaul Moore def_bool y 5507a017721SAKASHI Takahiro depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 55128a3a7ebSEric Paris select FSNOTIFY 55274c3cbe3SAl Viro 553d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 554764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 555b24abcffSDaniel Borkmannsource "kernel/bpf/Kconfig" 55687a4c375SChristoph Hellwigsource "kernel/Kconfig.preempt" 557d9817ebeSThomas Gleixner 558391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 559391dc69cSFrederic Weisbecker 560abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 561abf917cdSFrederic Weisbecker bool 562abf917cdSFrederic Weisbecker 563fdf9c356SFrederic Weisbeckerchoice 564fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 56502382affSNicholas Piggin default TICK_CPU_ACCOUNTING 566fdf9c356SFrederic Weisbecker 567fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 568fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 569fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 570c58b0df1SFrederic Weisbecker depends on !S390 && !NO_HZ_FULL 571fdf9c356SFrederic Weisbecker help 572fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 573fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 574fdf9c356SFrederic Weisbecker granularity. 575fdf9c356SFrederic Weisbecker 576fdf9c356SFrederic Weisbecker If unsure, say Y. 577fdf9c356SFrederic Weisbecker 578abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE 579391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 580c58b0df1SFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 581abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 582391dc69cSFrederic Weisbecker help 583391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 584391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 585391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 586391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 587391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 588391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 589391dc69cSFrederic Weisbecker systems. 590391dc69cSFrederic Weisbecker 591abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN 592abf917cdSFrederic Weisbecker bool "Full dynticks CPU time accounting" 59324a9c541SFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING_USER 594554b0004SKevin Hilman depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 595041a1574SArnd Bergmann depends on GENERIC_CLOCKEVENTS 596abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 59724a9c541SFrederic Weisbecker select CONTEXT_TRACKING_USER 598abf917cdSFrederic Weisbecker help 599abf917cdSFrederic Weisbecker Select this option to enable task and CPU time accounting on full 600abf917cdSFrederic Weisbecker dynticks systems. This accounting is implemented by watching every 601abf917cdSFrederic Weisbecker kernel-user boundaries using the context tracking subsystem. 602abf917cdSFrederic Weisbecker The accounting is thus performed at the expense of some significant 603abf917cdSFrederic Weisbecker overhead. 604abf917cdSFrederic Weisbecker 605abf917cdSFrederic Weisbecker For now this is only useful if you are working on the full 606abf917cdSFrederic Weisbecker dynticks subsystem development. 607abf917cdSFrederic Weisbecker 608abf917cdSFrederic Weisbecker If unsure, say N. 609abf917cdSFrederic Weisbecker 610b58c3584SRik van Rielendchoice 611b58c3584SRik van Riel 612fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 613fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 614b58c3584SRik van Riel depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 615fdf9c356SFrederic Weisbecker help 616fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 617fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 618fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 619fdf9c356SFrederic Weisbecker small performance impact. 620fdf9c356SFrederic Weisbecker 621fdf9c356SFrederic Weisbecker If in doubt, say N here. 622fdf9c356SFrederic Weisbecker 62311d4afd4SVincent Guittotconfig HAVE_SCHED_AVG_IRQ 62411d4afd4SVincent Guittot def_bool y 62511d4afd4SVincent Guittot depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 62611d4afd4SVincent Guittot depends on SMP 62711d4afd4SVincent Guittot 628d4dbc991SVincent Guittotconfig SCHED_HW_PRESSURE 62998eb401dSValentin Schneider bool 630fcd7c9c3SValentin Schneider default y if ARM && ARM_CPU_TOPOLOGY 631fcd7c9c3SValentin Schneider default y if ARM64 63276504793SThara Gopinath depends on SMP 63398eb401dSValentin Schneider depends on CPU_FREQ_THERMAL 63498eb401dSValentin Schneider help 635d4dbc991SVincent Guittot Select this option to enable HW pressure accounting in the 636d4dbc991SVincent Guittot scheduler. HW pressure is the value conveyed to the scheduler 63798eb401dSValentin Schneider that reflects the reduction in CPU compute capacity resulted from 638d4dbc991SVincent Guittot HW throttling. HW throttling occurs when the performance of 639d4dbc991SVincent Guittot a CPU is capped due to high operating temperatures as an example. 64098eb401dSValentin Schneider 64198eb401dSValentin Schneider If selected, the scheduler will be able to balance tasks accordingly, 64298eb401dSValentin Schneider i.e. put less load on throttled CPUs than on non/less throttled ones. 64398eb401dSValentin Schneider 64498eb401dSValentin Schneider This requires the architecture to implement 645d4dbc991SVincent Guittot arch_update_hw_pressure() and arch_scale_thermal_pressure(). 64676504793SThara Gopinath 647391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 64846329a9dSJeff Layton bool "BSD Process Accounting (DEPRECATED)" 6492813893fSIulia Manda depends on MULTIUSER 65046329a9dSJeff Layton default n 651391dc69cSFrederic Weisbecker help 652391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 653391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 654391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 655391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 656391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 657391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 658391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 659391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 66046329a9dSJeff Layton information. This mechanism is antiquated and has significant 66146329a9dSJeff Layton scalability issues. You probably want to use eBPF instead. Say 66246329a9dSJeff Layton N unless you really need this. 663391dc69cSFrederic Weisbecker 664391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 665391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 666391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 667391dc69cSFrederic Weisbecker default n 668391dc69cSFrederic Weisbecker help 669391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 670391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 6713903bf94SRandy Dunlap process and its parent. Note that this file format is incompatible 672391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 673391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 674391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 675391dc69cSFrederic Weisbecker 676391dc69cSFrederic Weisbeckerconfig TASKSTATS 67719c92399SKees Cook bool "Export task/process statistics through netlink" 678391dc69cSFrederic Weisbecker depends on NET 6792813893fSIulia Manda depends on MULTIUSER 680391dc69cSFrederic Weisbecker default n 681391dc69cSFrederic Weisbecker help 682391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 683391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 684391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 685391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 686391dc69cSFrederic Weisbecker space on task exit. 687391dc69cSFrederic Weisbecker 688391dc69cSFrederic Weisbecker Say N if unsure. 689391dc69cSFrederic Weisbecker 690391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 69119c92399SKees Cook bool "Enable per-task delay accounting" 692391dc69cSFrederic Weisbecker depends on TASKSTATS 693f6db8347SNaveen N. Rao select SCHED_INFO 694391dc69cSFrederic Weisbecker help 695391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 696391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 697391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 698391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 699391dc69cSFrederic Weisbecker 700391dc69cSFrederic Weisbecker Say N if unsure. 701391dc69cSFrederic Weisbecker 702391dc69cSFrederic Weisbeckerconfig TASK_XACCT 70319c92399SKees Cook bool "Enable extended accounting over taskstats" 704391dc69cSFrederic Weisbecker depends on TASKSTATS 705391dc69cSFrederic Weisbecker help 706391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 707391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 708391dc69cSFrederic Weisbecker 709391dc69cSFrederic Weisbecker Say N if unsure. 710391dc69cSFrederic Weisbecker 711391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 71219c92399SKees Cook bool "Enable per-task storage I/O accounting" 713391dc69cSFrederic Weisbecker depends on TASK_XACCT 714391dc69cSFrederic Weisbecker help 715391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 716391dc69cSFrederic Weisbecker task has caused. 717391dc69cSFrederic Weisbecker 718391dc69cSFrederic Weisbecker Say N if unsure. 719391dc69cSFrederic Weisbecker 720eb414681SJohannes Weinerconfig PSI 721eb414681SJohannes Weiner bool "Pressure stall information tracking" 72298dfdd9eSRandy Dunlap select KERNFS 723eb414681SJohannes Weiner help 724eb414681SJohannes Weiner Collect metrics that indicate how overcommitted the CPU, memory, 725eb414681SJohannes Weiner and IO capacity are in the system. 726eb414681SJohannes Weiner 727eb414681SJohannes Weiner If you say Y here, the kernel will create /proc/pressure/ with the 728eb414681SJohannes Weiner pressure statistics files cpu, memory, and io. These will indicate 729eb414681SJohannes Weiner the share of walltime in which some or all tasks in the system are 730eb414681SJohannes Weiner delayed due to contention of the respective resource. 731eb414681SJohannes Weiner 7322ce7135aSJohannes Weiner In kernels with cgroup support, cgroups (cgroup2 only) will 7332ce7135aSJohannes Weiner have cpu.pressure, memory.pressure, and io.pressure files, 7342ce7135aSJohannes Weiner which aggregate pressure stalls for the grouped tasks only. 7352ce7135aSJohannes Weiner 736c3123552SMauro Carvalho Chehab For more details see Documentation/accounting/psi.rst. 737eb414681SJohannes Weiner 738eb414681SJohannes Weiner Say N if unsure. 739eb414681SJohannes Weiner 740e0c27447SJohannes Weinerconfig PSI_DEFAULT_DISABLED 741e0c27447SJohannes Weiner bool "Require boot parameter to enable pressure stall information tracking" 742e0c27447SJohannes Weiner default n 743e0c27447SJohannes Weiner depends on PSI 744e0c27447SJohannes Weiner help 745e0c27447SJohannes Weiner If set, pressure stall information tracking will be disabled 746428a1cb4SBaruch Siach per default but can be enabled through passing psi=1 on the 747428a1cb4SBaruch Siach kernel commandline during boot. 748e0c27447SJohannes Weiner 7497b2489d3SJohannes Weiner This feature adds some code to the task wakeup and sleep 7507b2489d3SJohannes Weiner paths of the scheduler. The overhead is too low to affect 7517b2489d3SJohannes Weiner common scheduling-intense workloads in practice (such as 7527b2489d3SJohannes Weiner webservers, memcache), but it does show up in artificial 7537b2489d3SJohannes Weiner scheduler stress tests, such as hackbench. 7547b2489d3SJohannes Weiner 7557b2489d3SJohannes Weiner If you are paranoid and not sure what the kernel will be 7567b2489d3SJohannes Weiner used for, say Y. 7577b2489d3SJohannes Weiner 7587b2489d3SJohannes Weiner Say N if unsure. 7597b2489d3SJohannes Weiner 760391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 761391dc69cSFrederic Weisbecker 7625c4991e2SFrederic Weisbeckerconfig CPU_ISOLATION 7635c4991e2SFrederic Weisbecker bool "CPU isolation" 76497577684SOleg Nesterov depends on SMP 7652c43838cSFrederic Weisbecker default y 7665c4991e2SFrederic Weisbecker help 7675c4991e2SFrederic Weisbecker Make sure that CPUs running critical tasks are not disturbed by 7685c4991e2SFrederic Weisbecker any source of "noise" such as unbound workqueues, timers, kthreads... 7692c43838cSFrederic Weisbecker Unbound jobs get offloaded to housekeeping CPUs. This is driven by 7702c43838cSFrederic Weisbecker the "isolcpus=" boot parameter. 7712c43838cSFrederic Weisbecker 7722c43838cSFrederic Weisbecker Say Y if unsure. 7735c4991e2SFrederic Weisbecker 7740af92d46SPaul E. McKenneysource "kernel/rcu/Kconfig" 775c903ff83SMike Travis 7761da177e4SLinus Torvaldsconfig IKCONFIG 777f2443ab6SRoss Biro tristate "Kernel .config support" 778a7f7f624SMasahiro Yamada help 7791da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 7801da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 7811da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 7821da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 7831da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 7841da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 7851da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 7861da177e4SLinus Torvalds /proc/config.gz if enabled (below). 7871da177e4SLinus Torvalds 7881da177e4SLinus Torvaldsconfig IKCONFIG_PROC 7891da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 7901da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 791a7f7f624SMasahiro Yamada help 7921da177e4SLinus Torvalds This option enables access to the kernel configuration file 7931da177e4SLinus Torvalds through /proc/config.gz. 7941da177e4SLinus Torvalds 795f7b101d3SJoel Fernandes (Google)config IKHEADERS 796f7b101d3SJoel Fernandes (Google) tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 797f7b101d3SJoel Fernandes (Google) depends on SYSFS 79843d8ce9dSJoel Fernandes (Google) help 799f7b101d3SJoel Fernandes (Google) This option enables access to the in-kernel headers that are generated during 800f7b101d3SJoel Fernandes (Google) the build process. These can be used to build eBPF tracing programs, 801f7b101d3SJoel Fernandes (Google) or similar programs. If you build the headers as a module, a module called 802f7b101d3SJoel Fernandes (Google) kheaders.ko is built which can be loaded on-demand to get access to headers. 80343d8ce9dSJoel Fernandes (Google) 804794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 805794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 8061c4b5ecbSChristoph Hellwig range 12 25 807f17a32e9SAdrian Bunk default 17 808361e9dfbSJosh Triplett depends on PRINTK 809794543a2SAlistair John Strachan help 81023b2899fSLuis R. Rodriguez Select the minimal kernel log buffer size as a power of 2. 81123b2899fSLuis R. Rodriguez The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 81223b2899fSLuis R. Rodriguez parameter, see below. Any higher size also might be forced 81323b2899fSLuis R. Rodriguez by "log_buf_len" boot parameter. 81423b2899fSLuis R. Rodriguez 815f17a32e9SAdrian Bunk Examples: 816f17a32e9SAdrian Bunk 17 => 128 KB 817f17a32e9SAdrian Bunk 16 => 64 KB 818f17a32e9SAdrian Bunk 15 => 32 KB 819f17a32e9SAdrian Bunk 14 => 16 KB 820794543a2SAlistair John Strachan 13 => 8 KB 821794543a2SAlistair John Strachan 12 => 4 KB 822794543a2SAlistair John Strachan 82323b2899fSLuis R. Rodriguezconfig LOG_CPU_MAX_BUF_SHIFT 82423b2899fSLuis R. Rodriguez int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 8252240a31dSGeert Uytterhoeven depends on SMP 82623b2899fSLuis R. Rodriguez range 0 21 82723b2899fSLuis R. Rodriguez default 0 if BASE_SMALL 828320bf431SYoann Congal default 12 829361e9dfbSJosh Triplett depends on PRINTK 83023b2899fSLuis R. Rodriguez help 83123b2899fSLuis R. Rodriguez This option allows to increase the default ring buffer size 83223b2899fSLuis R. Rodriguez according to the number of CPUs. The value defines the contribution 83323b2899fSLuis R. Rodriguez of each CPU as a power of 2. The used space is typically only few 83423b2899fSLuis R. Rodriguez lines however it might be much more when problems are reported, 83523b2899fSLuis R. Rodriguez e.g. backtraces. 83623b2899fSLuis R. Rodriguez 83723b2899fSLuis R. Rodriguez The increased size means that a new buffer has to be allocated and 83823b2899fSLuis R. Rodriguez the original static one is unused. It makes sense only on systems 83923b2899fSLuis R. Rodriguez with more CPUs. Therefore this value is used only when the sum of 84023b2899fSLuis R. Rodriguez contributions is greater than the half of the default kernel ring 84123b2899fSLuis R. Rodriguez buffer as defined by LOG_BUF_SHIFT. The default values are set 8420f7636e1SPaul Menzel so that more than 16 CPUs are needed to trigger the allocation. 84323b2899fSLuis R. Rodriguez 84423b2899fSLuis R. Rodriguez Also this option is ignored when "log_buf_len" kernel parameter is 84523b2899fSLuis R. Rodriguez used as it forces an exact (power of two) size of the ring buffer. 84623b2899fSLuis R. Rodriguez 84723b2899fSLuis R. Rodriguez The number of possible CPUs is used for this computation ignoring 8485e0d8d59SGeert Uytterhoeven hotplugging making the computation optimal for the worst case 8495e0d8d59SGeert Uytterhoeven scenario while allowing a simple algorithm to be used from bootup. 85023b2899fSLuis R. Rodriguez 85123b2899fSLuis R. Rodriguez Examples shift values and their meaning: 85223b2899fSLuis R. Rodriguez 17 => 128 KB for each CPU 85323b2899fSLuis R. Rodriguez 16 => 64 KB for each CPU 85423b2899fSLuis R. Rodriguez 15 => 32 KB for each CPU 85523b2899fSLuis R. Rodriguez 14 => 16 KB for each CPU 85623b2899fSLuis R. Rodriguez 13 => 8 KB for each CPU 85723b2899fSLuis R. Rodriguez 12 => 4 KB for each CPU 85823b2899fSLuis R. Rodriguez 85933701557SChris Downconfig PRINTK_INDEX 86033701557SChris Down bool "Printk indexing debugfs interface" 86133701557SChris Down depends on PRINTK && DEBUG_FS 86233701557SChris Down help 86333701557SChris Down Add support for indexing of all printk formats known at compile time 86433701557SChris Down at <debugfs>/printk/index/<module>. 86533701557SChris Down 86633701557SChris Down This can be used as part of maintaining daemons which monitor 86733701557SChris Down /dev/kmsg, as it permits auditing the printk formats present in a 86833701557SChris Down kernel, allowing detection of cases where monitored printks are 86933701557SChris Down changed or no longer present. 87033701557SChris Down 87133701557SChris Down There is no additional runtime cost to printk with this enabled. 87233701557SChris Down 8735cdc38f9SKAMEZAWA Hiroyuki# 8745cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 8755cdc38f9SKAMEZAWA Hiroyuki# 8765cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 8775cdc38f9SKAMEZAWA Hiroyuki bool 8785cdc38f9SKAMEZAWA Hiroyuki 87938ff87f7SStephen Boydconfig GENERIC_SCHED_CLOCK 88038ff87f7SStephen Boyd bool 88138ff87f7SStephen Boyd 88269842cbaSPatrick Bellasimenu "Scheduler features" 88369842cbaSPatrick Bellasi 88469842cbaSPatrick Bellasiconfig UCLAMP_TASK 88569842cbaSPatrick Bellasi bool "Enable utilization clamping for RT/FAIR tasks" 88669842cbaSPatrick Bellasi depends on CPU_FREQ_GOV_SCHEDUTIL 88769842cbaSPatrick Bellasi help 88869842cbaSPatrick Bellasi This feature enables the scheduler to track the clamped utilization 88969842cbaSPatrick Bellasi of each CPU based on RUNNABLE tasks scheduled on that CPU. 89069842cbaSPatrick Bellasi 89169842cbaSPatrick Bellasi With this option, the user can specify the min and max CPU 89269842cbaSPatrick Bellasi utilization allowed for RUNNABLE tasks. The max utilization defines 89369842cbaSPatrick Bellasi the maximum frequency a task should use while the min utilization 89469842cbaSPatrick Bellasi defines the minimum frequency it should use. 89569842cbaSPatrick Bellasi 89669842cbaSPatrick Bellasi Both min and max utilization clamp values are hints to the scheduler, 89769842cbaSPatrick Bellasi aiming at improving its frequency selection policy, but they do not 89869842cbaSPatrick Bellasi enforce or grant any specific bandwidth for tasks. 89969842cbaSPatrick Bellasi 90069842cbaSPatrick Bellasi If in doubt, say N. 90169842cbaSPatrick Bellasi 90269842cbaSPatrick Bellasiconfig UCLAMP_BUCKETS_COUNT 90369842cbaSPatrick Bellasi int "Number of supported utilization clamp buckets" 90469842cbaSPatrick Bellasi range 5 20 90569842cbaSPatrick Bellasi default 5 90669842cbaSPatrick Bellasi depends on UCLAMP_TASK 90769842cbaSPatrick Bellasi help 90869842cbaSPatrick Bellasi Defines the number of clamp buckets to use. The range of each bucket 90969842cbaSPatrick Bellasi will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 91069842cbaSPatrick Bellasi number of clamp buckets the finer their granularity and the higher 91169842cbaSPatrick Bellasi the precision of clamping aggregation and tracking at run-time. 91269842cbaSPatrick Bellasi 91369842cbaSPatrick Bellasi For example, with the minimum configuration value we will have 5 91469842cbaSPatrick Bellasi clamp buckets tracking 20% utilization each. A 25% boosted tasks will 91569842cbaSPatrick Bellasi be refcounted in the [20..39]% bucket and will set the bucket clamp 91669842cbaSPatrick Bellasi effective value to 25%. 91769842cbaSPatrick Bellasi If a second 30% boosted task should be co-scheduled on the same CPU, 91869842cbaSPatrick Bellasi that task will be refcounted in the same bucket of the first task and 91969842cbaSPatrick Bellasi it will boost the bucket clamp effective value to 30%. 92069842cbaSPatrick Bellasi The clamp effective value of a bucket is reset to its nominal value 92169842cbaSPatrick Bellasi (20% in the example above) when there are no more tasks refcounted in 92269842cbaSPatrick Bellasi that bucket. 92369842cbaSPatrick Bellasi 92469842cbaSPatrick Bellasi An additional boost/capping margin can be added to some tasks. In the 92569842cbaSPatrick Bellasi example above the 25% task will be boosted to 30% until it exits the 92669842cbaSPatrick Bellasi CPU. If that should be considered not acceptable on certain systems, 92769842cbaSPatrick Bellasi it's always possible to reduce the margin by increasing the number of 92869842cbaSPatrick Bellasi clamp buckets to trade off used memory for run-time tracking 92969842cbaSPatrick Bellasi precision. 93069842cbaSPatrick Bellasi 93169842cbaSPatrick Bellasi If in doubt, use the default value. 93269842cbaSPatrick Bellasi 93325c411fcSJohn Stultzconfig SCHED_PROXY_EXEC 93425c411fcSJohn Stultz bool "Proxy Execution" 93525c411fcSJohn Stultz # Avoid some build failures w/ PREEMPT_RT until it can be fixed 93625c411fcSJohn Stultz depends on !PREEMPT_RT 93725c411fcSJohn Stultz # Need to investigate how to inform sched_ext of split contexts 93825c411fcSJohn Stultz depends on !SCHED_CLASS_EXT 93925c411fcSJohn Stultz # Not particularly useful until we get to multi-rq proxying 94025c411fcSJohn Stultz depends on EXPERT 94125c411fcSJohn Stultz help 94225c411fcSJohn Stultz This option enables proxy execution, a mechanism for mutex-owning 94325c411fcSJohn Stultz tasks to inherit the scheduling context of higher priority waiters. 94425c411fcSJohn Stultz 94569842cbaSPatrick Bellasiendmenu 94669842cbaSPatrick Bellasi 947be3a7284SAndrea Arcangeli# 948be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler 949be3a7284SAndrea Arcangeli# balancing logic: 950be3a7284SAndrea Arcangeli# 951be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING 952be3a7284SAndrea Arcangeli bool 953be3a7284SAndrea Arcangeli 954be5e610cSPeter Zijlstra# 95572b252aeSMel Gorman# For architectures that prefer to flush all TLBs after a number of pages 95672b252aeSMel Gorman# are unmapped instead of sending one IPI per page to flush. The architecture 95772b252aeSMel Gorman# must provide guarantees on what happens if a clean TLB cache entry is 95872b252aeSMel Gorman# written after the unmap. Details are in mm/rmap.c near the check for 95972b252aeSMel Gorman# should_defer_flush. The architecture should also consider if the full flush 96072b252aeSMel Gorman# and the refill costs are offset by the savings of sending fewer IPIs. 96172b252aeSMel Gormanconfig ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 96272b252aeSMel Gorman bool 96372b252aeSMel Gorman 964c12d3362SArd Biesheuvelconfig CC_HAS_INT128 9653a7c7331SMasahiro Yamada def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 966c12d3362SArd Biesheuvel 967dee2b702SGustavo A. R. Silvaconfig CC_IMPLICIT_FALLTHROUGH 968dee2b702SGustavo A. R. Silva string 969158ea2d2SGustavo A. R. Silva default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 970dee2b702SGustavo A. R. Silva default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 971dee2b702SGustavo A. R. Silva 9720d3fccf6SNathan Chancellorconfig CC_MS_EXTENSIONS 9730d3fccf6SNathan Chancellor string 9740d3fccf6SNathan Chancellor default "-fms-anonymous-structs" if $(cc-option,-fms-anonymous-structs) 9750d3fccf6SNathan Chancellor default "-fms-extensions" 9760d3fccf6SNathan Chancellor 9773e00f580SKees Cook# Currently, disable gcc-10+ array-bounds globally. 9780da6e5fdSLinus Torvalds# It's still broken in gcc-13, so no upper bound yet. 9793e00f580SKees Cookconfig GCC10_NO_ARRAY_BOUNDS 9805a41237aSLinus Torvalds def_bool y 9815a41237aSLinus Torvalds 982f0be87c4SLinus Torvaldsconfig CC_NO_ARRAY_BOUNDS 983f0be87c4SLinus Torvalds bool 9848e5bd4eaSYury Norov default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 985f0be87c4SLinus Torvalds 98602153319SLinus Torvalds# Currently, disable -Wstringop-overflow for GCC globally. 98702153319SLinus Torvaldsconfig GCC_NO_STRINGOP_OVERFLOW 988a5e0ace0SGustavo A. R. Silva def_bool y 989a5e0ace0SGustavo A. R. Silva 990a5e0ace0SGustavo A. R. Silvaconfig CC_NO_STRINGOP_OVERFLOW 991a5e0ace0SGustavo A. R. Silva bool 99202153319SLinus Torvalds default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 993a5e0ace0SGustavo A. R. Silva 994a5e0ace0SGustavo A. R. Silvaconfig CC_STRINGOP_OVERFLOW 995a5e0ace0SGustavo A. R. Silva bool 996a5e0ace0SGustavo A. R. Silva default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 997a5e0ace0SGustavo A. R. Silva 99872b252aeSMel Gorman# 999be5e610cSPeter Zijlstra# For architectures that know their GCC __int128 support is sound 1000be5e610cSPeter Zijlstra# 1001be5e610cSPeter Zijlstraconfig ARCH_SUPPORTS_INT128 1002be5e610cSPeter Zijlstra bool 1003be5e610cSPeter Zijlstra 1004be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions 1005be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH. 1006be3a7284SAndrea Arcangeli# 1007be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY 1008be3a7284SAndrea Arcangeli bool 1009be3a7284SAndrea Arcangeli 1010be3a7284SAndrea Arcangeliconfig NUMA_BALANCING 1011be3a7284SAndrea Arcangeli bool "Memory placement aware NUMA scheduler" 1012be3a7284SAndrea Arcangeli depends on ARCH_SUPPORTS_NUMA_BALANCING 1013be3a7284SAndrea Arcangeli depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 10146ebf98d7SDavid Hildenbrand (Arm) depends on SMP && NUMA_MIGRATION && !PREEMPT_RT 1015be3a7284SAndrea Arcangeli help 1016be3a7284SAndrea Arcangeli This option adds support for automatic NUMA aware memory/task placement. 1017be3a7284SAndrea Arcangeli The mechanism is quite primitive and is based on migrating memory when 10186d56a410SPaul Gortmaker it has references to the node the task is running on. 1019be3a7284SAndrea Arcangeli 1020be3a7284SAndrea Arcangeli This system will be inactive on UMA systems. 1021be3a7284SAndrea Arcangeli 1022df0d9847SPeter Zijlstra (Intel)config SCHED_CACHE 1023df0d9847SPeter Zijlstra (Intel) bool "Cache aware load balance" 1024df0d9847SPeter Zijlstra (Intel) default y 1025df0d9847SPeter Zijlstra (Intel) depends on SMP 1026df0d9847SPeter Zijlstra (Intel) help 1027df0d9847SPeter Zijlstra (Intel) When enabled, the scheduler will attempt to aggregate tasks from 1028df0d9847SPeter Zijlstra (Intel) the same process onto a single Last Level Cache (LLC) domain when 1029df0d9847SPeter Zijlstra (Intel) possible. This improves cache locality by keeping tasks that share 1030df0d9847SPeter Zijlstra (Intel) resources within the same cache domain, reducing cache misses and 1031df0d9847SPeter Zijlstra (Intel) lowering data access latency. 1032df0d9847SPeter Zijlstra (Intel) 10336f7c97e8SAneesh Kumar K.Vconfig NUMA_BALANCING_DEFAULT_ENABLED 10346f7c97e8SAneesh Kumar K.V bool "Automatically enable NUMA aware memory/task placement" 10356f7c97e8SAneesh Kumar K.V default y 10366f7c97e8SAneesh Kumar K.V depends on NUMA_BALANCING 10376f7c97e8SAneesh Kumar K.V help 10386f7c97e8SAneesh Kumar K.V If set, automatic NUMA balancing will be enabled if running on a NUMA 10396f7c97e8SAneesh Kumar K.V machine. 10406f7c97e8SAneesh Kumar K.V 104121c690a3SSuren Baghdasaryanconfig SLAB_OBJ_EXT 104221c690a3SSuren Baghdasaryan bool 104321c690a3SSuren Baghdasaryan 104423964d2dSLi Zefanmenuconfig CGROUPS 10456341e62bSChristoph Jaeger bool "Control Group support" 10462bd59d48STejun Heo select KERNFS 1047ddbcc7e8SPaul Menage help 104823964d2dSLi Zefan This option adds support for grouping sets of processes together, for 10495cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 10505cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 10515cdc38f9SKAMEZAWA Hiroyuki See 1052d6a3b247SMauro Carvalho Chehab - Documentation/scheduler/sched-design-CFS.rst (CFS) 1053da82c92fSMauro Carvalho Chehab - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 105445ce80fbSLi Zefan and resource control) 1055ddbcc7e8SPaul Menage 1056ddbcc7e8SPaul Menage Say N if unsure. 1057ddbcc7e8SPaul Menage 105823964d2dSLi Zefanif CGROUPS 105923964d2dSLi Zefan 10603e32cb2eSJohannes Weinerconfig PAGE_COUNTER 10613e32cb2eSJohannes Weiner bool 10623e32cb2eSJohannes Weiner 10636a010a49STejun Heoconfig CGROUP_FAVOR_DYNMODS 10646a010a49STejun Heo bool "Favor dynamic modification latency reduction by default" 10656a010a49STejun Heo help 10666a010a49STejun Heo This option enables the "favordynmods" mount option by default 10676a010a49STejun Heo which reduces the latencies of dynamic cgroup modifications such 10686a010a49STejun Heo as task migrations and controller on/offs at the cost of making 10696a010a49STejun Heo hot path operations such as forks and exits more expensive. 10706a010a49STejun Heo 10716a010a49STejun Heo Say N if unsure. 10726a010a49STejun Heo 1073c255a458SAndrew Mortonconfig MEMCG 1074a0166ec4SJohannes Weiner bool "Memory controller" 10753e32cb2eSJohannes Weiner select PAGE_COUNTER 107679bd9814STejun Heo select EVENTFD 107721c690a3SSuren Baghdasaryan select SLAB_OBJ_EXT 1078fdc5001bSKirill A. Shutemov select VM_EVENT_COUNTERS 107900f0b825SBalbir Singh help 1080a0166ec4SJohannes Weiner Provides control over the memory footprint of tasks in a cgroup. 108100f0b825SBalbir Singh 108225352d2fSShakeel Buttconfig MEMCG_NMI_UNSAFE 108325352d2fSShakeel Butt bool 108425352d2fSShakeel Butt depends on MEMCG 108525352d2fSShakeel Butt depends on HAVE_NMI 108625352d2fSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 108725352d2fSShakeel Butt default y 108825352d2fSShakeel Butt 1089940b01fcSShakeel Buttconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1090940b01fcSShakeel Butt bool 1091940b01fcSShakeel Butt depends on MEMCG 1092940b01fcSShakeel Butt depends on HAVE_NMI 1093940b01fcSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1094940b01fcSShakeel Butt default y 1095940b01fcSShakeel Butt 1096e93d4166SRoman Gushchinconfig MEMCG_V1 1097e93d4166SRoman Gushchin bool "Legacy cgroup v1 memory controller" 1098c9929f0eSVlastimil Babka depends on MEMCG 1099e93d4166SRoman Gushchin default n 1100e93d4166SRoman Gushchin help 1101e93d4166SRoman Gushchin Legacy cgroup v1 memory controller which has been deprecated by 1102e93d4166SRoman Gushchin cgroup v2 implementation. The v1 is there for legacy applications 1103e93d4166SRoman Gushchin which haven't migrated to the new cgroup v2 interface yet. If you 1104e93d4166SRoman Gushchin do not have any such application then you are completely fine leaving 1105e93d4166SRoman Gushchin this option disabled. 1106e93d4166SRoman Gushchin 1107e93d4166SRoman Gushchin Please note that feature set of the legacy memory controller is likely 1108e93d4166SRoman Gushchin going to shrink due to deprecation process. New deployments with v1 1109e93d4166SRoman Gushchin controller are highly discouraged. 1110e93d4166SRoman Gushchin 1111fcb4824bSValdis Kletnieks Say N if unsure. 111284c07d11SKirill Tkhai 11136bf024e6SJohannes Weinerconfig BLK_CGROUP 11146bf024e6SJohannes Weiner bool "IO controller" 11156bf024e6SJohannes Weiner depends on BLOCK 11162bc64a20SAneesh Kumar K.V default n 1117a7f7f624SMasahiro Yamada help 11186bf024e6SJohannes Weiner Generic block IO controller cgroup interface. This is the common 11196bf024e6SJohannes Weiner cgroup interface which should be used by various IO controlling 11206bf024e6SJohannes Weiner policies. 11212bc64a20SAneesh Kumar K.V 11226bf024e6SJohannes Weiner Currently, CFQ IO scheduler uses it to recognize task groups and 11236bf024e6SJohannes Weiner control disk bandwidth allocation (proportional time slice allocation) 11246bf024e6SJohannes Weiner to such task groups. It is also used by bio throttling logic in 11256bf024e6SJohannes Weiner block layer to implement upper limit in IO rates on a device. 1126e5d1367fSStephane Eranian 11276bf024e6SJohannes Weiner This option only enables generic Block IO controller infrastructure. 11286bf024e6SJohannes Weiner One needs to also enable actual IO controlling logic/policy. For 11296bf024e6SJohannes Weiner enabling proportional weight division of disk bandwidth in CFQ, set 11307baf2199SKrzysztof Kozlowski CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 11316bf024e6SJohannes Weiner CONFIG_BLK_DEV_THROTTLING=y. 11326bf024e6SJohannes Weiner 1133da82c92fSMauro Carvalho Chehab See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 11346bf024e6SJohannes Weiner 11356bf024e6SJohannes Weinerconfig CGROUP_WRITEBACK 11366bf024e6SJohannes Weiner bool 11376bf024e6SJohannes Weiner depends on MEMCG && BLK_CGROUP 11386bf024e6SJohannes Weiner default y 1139e5d1367fSStephane Eranian 11407c941438SDhaval Gianimenuconfig CGROUP_SCHED 1141a0166ec4SJohannes Weiner bool "CPU controller" 11427c941438SDhaval Giani default n 11437c941438SDhaval Giani help 11447c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 11457c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 11467c941438SDhaval Giani tasks. 11477c941438SDhaval Giani 11487c941438SDhaval Gianiif CGROUP_SCHED 1149e179e80cSTejun Heoconfig GROUP_SCHED_WEIGHT 1150e179e80cSTejun Heo def_bool n 1151e179e80cSTejun Heo 1152ddceadceSTejun Heoconfig GROUP_SCHED_BANDWIDTH 1153ddceadceSTejun Heo def_bool n 1154ddceadceSTejun Heo 11557c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 11567c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 11577c941438SDhaval Giani depends on CGROUP_SCHED 1158e179e80cSTejun Heo select GROUP_SCHED_WEIGHT 11597c941438SDhaval Giani default CGROUP_SCHED 11607c941438SDhaval Giani 1161ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 1162ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1163ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 1164ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 1165ab84d31eSPaul Turner default n 1166ab84d31eSPaul Turner help 1167ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 1168ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 1169ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 1170ab84d31eSPaul Turner restriction. 1171d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-bwc.rst for more information. 1172ab84d31eSPaul Turner 11737c941438SDhaval Gianiconfig RT_GROUP_SCHED 11747c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 11757c941438SDhaval Giani depends on CGROUP_SCHED 11767c941438SDhaval Giani default n 11777c941438SDhaval Giani help 11787c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 117932bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 11807c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 11817c941438SDhaval Giani realtime bandwidth for them. 1182d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-rt-group.rst for more information. 11837c941438SDhaval Giani 1184e34e0131SMichal Koutnýconfig RT_GROUP_SCHED_DEFAULT_DISABLED 1185e34e0131SMichal Koutný bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1186e34e0131SMichal Koutný depends on RT_GROUP_SCHED 1187e34e0131SMichal Koutný default n 1188e34e0131SMichal Koutný help 1189e34e0131SMichal Koutný When set, the RT group scheduling is disabled by default. The option 1190e34e0131SMichal Koutný is in inverted form so that mere RT_GROUP_SCHED enables the group 1191e34e0131SMichal Koutný scheduling. 1192e34e0131SMichal Koutný 1193e34e0131SMichal Koutný Say N if unsure. 1194e34e0131SMichal Koutný 119581951366STejun Heoconfig EXT_GROUP_SCHED 119681951366STejun Heo bool 119781951366STejun Heo depends on SCHED_CLASS_EXT && CGROUP_SCHED 119881951366STejun Heo select GROUP_SCHED_WEIGHT 1199ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 120081951366STejun Heo default y 120181951366STejun Heo 12027c941438SDhaval Gianiendif #CGROUP_SCHED 12037c941438SDhaval Giani 1204ebeca1f9STejun Heoconfig EXT_SUB_SCHED 1205ebeca1f9STejun Heo def_bool y 1206e73b1d72SCheng-Yang Chou depends on SCHED_CLASS_EXT && CGROUPS 1207ebeca1f9STejun Heo 1208af7f588dSMathieu Desnoyersconfig SCHED_MM_CID 1209af7f588dSMathieu Desnoyers def_bool y 1210af7f588dSMathieu Desnoyers depends on SMP && RSEQ 1211af7f588dSMathieu Desnoyers 12122480c093SPatrick Bellasiconfig UCLAMP_TASK_GROUP 12132480c093SPatrick Bellasi bool "Utilization clamping per group of tasks" 12142480c093SPatrick Bellasi depends on CGROUP_SCHED 12152480c093SPatrick Bellasi depends on UCLAMP_TASK 12162480c093SPatrick Bellasi default n 12172480c093SPatrick Bellasi help 12182480c093SPatrick Bellasi This feature enables the scheduler to track the clamped utilization 12192480c093SPatrick Bellasi of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 12202480c093SPatrick Bellasi 12212480c093SPatrick Bellasi When this option is enabled, the user can specify a min and max 12222480c093SPatrick Bellasi CPU bandwidth which is allowed for each single task in a group. 12232480c093SPatrick Bellasi The max bandwidth allows to clamp the maximum frequency a task 12242480c093SPatrick Bellasi can use, while the min bandwidth allows to define a minimum 12252480c093SPatrick Bellasi frequency a task will always use. 12262480c093SPatrick Bellasi 12272480c093SPatrick Bellasi When task group based utilization clamping is enabled, an eventually 12282480c093SPatrick Bellasi specified task-specific clamp value is constrained by the cgroup 12292480c093SPatrick Bellasi specified clamp value. Both minimum and maximum task clamping cannot 12302480c093SPatrick Bellasi be bigger than the corresponding clamping defined at task group level. 12312480c093SPatrick Bellasi 12322480c093SPatrick Bellasi If in doubt, say N. 12332480c093SPatrick Bellasi 12346bf024e6SJohannes Weinerconfig CGROUP_PIDS 12356bf024e6SJohannes Weiner bool "PIDs controller" 12366bf024e6SJohannes Weiner help 12376bf024e6SJohannes Weiner Provides enforcement of process number limits in the scope of a 12386bf024e6SJohannes Weiner cgroup. Any attempt to fork more processes than is allowed in the 12396bf024e6SJohannes Weiner cgroup will fail. PIDs are fundamentally a global resource because it 12406bf024e6SJohannes Weiner is fairly trivial to reach PID exhaustion before you reach even a 12416bf024e6SJohannes Weiner conservative kmemcg limit. As a result, it is possible to grind a 12426bf024e6SJohannes Weiner system to halt without being limited by other cgroup policies. The 12436cc578dfSParav Pandit PIDs controller is designed to stop this from happening. 12446bf024e6SJohannes Weiner 12456bf024e6SJohannes Weiner It should be noted that organisational operations (such as attaching 124698076833SJonathan Neuschäfer to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 12476bf024e6SJohannes Weiner since the PIDs limit only affects a process's ability to fork, not to 12486bf024e6SJohannes Weiner attach to a cgroup. 12496bf024e6SJohannes Weiner 125039d3e758SParav Panditconfig CGROUP_RDMA 125139d3e758SParav Pandit bool "RDMA controller" 125239d3e758SParav Pandit help 125339d3e758SParav Pandit Provides enforcement of RDMA resources defined by IB stack. 125439d3e758SParav Pandit It is fairly easy for consumers to exhaust RDMA resources, which 125539d3e758SParav Pandit can result into resource unavailability to other consumers. 125639d3e758SParav Pandit RDMA controller is designed to stop this from happening. 125739d3e758SParav Pandit Attaching processes with active RDMA resources to the cgroup 125839d3e758SParav Pandit hierarchy is allowed even if can cross the hierarchy's limit. 125939d3e758SParav Pandit 1260b168ed45SMaarten Lankhorstconfig CGROUP_DMEM 1261b168ed45SMaarten Lankhorst bool "Device memory controller (DMEM)" 1262e33b5149SMaxime Ripard select PAGE_COUNTER 1263b168ed45SMaarten Lankhorst help 1264b168ed45SMaarten Lankhorst The DMEM controller allows compatible devices to restrict device 1265b168ed45SMaarten Lankhorst memory usage based on the cgroup hierarchy. 1266b168ed45SMaarten Lankhorst 1267b168ed45SMaarten Lankhorst As an example, it allows you to restrict VRAM usage for applications 1268b168ed45SMaarten Lankhorst in the DRM subsystem. 1269b168ed45SMaarten Lankhorst 12706bf024e6SJohannes Weinerconfig CGROUP_FREEZER 12716bf024e6SJohannes Weiner bool "Freezer controller" 12726bf024e6SJohannes Weiner help 12736bf024e6SJohannes Weiner Provides a way to freeze and unfreeze all tasks in a 12746bf024e6SJohannes Weiner cgroup. 12756bf024e6SJohannes Weiner 1276489c2a20SJohannes Weiner This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1277489c2a20SJohannes Weiner controller includes important in-kernel memory consumers per default. 1278489c2a20SJohannes Weiner 1279489c2a20SJohannes Weiner If you're using cgroup2, say N. 1280489c2a20SJohannes Weiner 12816bf024e6SJohannes Weinerconfig CGROUP_HUGETLB 12826bf024e6SJohannes Weiner bool "HugeTLB controller" 12836bf024e6SJohannes Weiner depends on HUGETLB_PAGE 12846bf024e6SJohannes Weiner select PAGE_COUNTER 1285afc24d49SVivek Goyal default n 12866bf024e6SJohannes Weiner help 12876bf024e6SJohannes Weiner Provides a cgroup controller for HugeTLB pages. 12886bf024e6SJohannes Weiner When you enable this, you can put a per cgroup limit on HugeTLB usage. 12896bf024e6SJohannes Weiner The limit is enforced during page fault. Since HugeTLB doesn't 12906bf024e6SJohannes Weiner support page reclaim, enforcing the limit at page fault time implies 12916bf024e6SJohannes Weiner that, the application will get SIGBUS signal if it tries to access 12926bf024e6SJohannes Weiner HugeTLB pages beyond its limit. This requires the application to know 12936bf024e6SJohannes Weiner beforehand how much HugeTLB pages it would require for its use. The 12946bf024e6SJohannes Weiner control group is tracked in the third page lru pointer. This means 12956bf024e6SJohannes Weiner that we cannot use the controller with huge page less than 3 pages. 1296afc24d49SVivek Goyal 12976bf024e6SJohannes Weinerconfig CPUSETS 12986bf024e6SJohannes Weiner bool "Cpuset controller" 1299e1d4eeecSNicolas Pitre depends on SMP 1300bf9850f6SKuan-Wei Chiu select UNION_FIND 130123f09dccSFrederic Weisbecker select CPU_ISOLATION 13026bf024e6SJohannes Weiner help 13036bf024e6SJohannes Weiner This option will let you create and manage CPUSETs which 13046bf024e6SJohannes Weiner allow dynamically partitioning a system into sets of CPUs and 13056bf024e6SJohannes Weiner Memory Nodes and assigning tasks to run only within those sets. 13066bf024e6SJohannes Weiner This is primarily useful on large SMP or NUMA systems. 1307afc24d49SVivek Goyal 13086bf024e6SJohannes Weiner Say N if unsure. 1309afc24d49SVivek Goyal 13101abab1baSChen Ridongconfig CPUSETS_V1 13111abab1baSChen Ridong bool "Legacy cgroup v1 cpusets controller" 13121abab1baSChen Ridong depends on CPUSETS 13131abab1baSChen Ridong default n 13141abab1baSChen Ridong help 13151abab1baSChen Ridong Legacy cgroup v1 cpusets controller which has been deprecated by 13161abab1baSChen Ridong cgroup v2 implementation. The v1 is there for legacy applications 1317dae68fbaSMichal Koutný which haven't migrated to the new cgroup v2 interface yet. Legacy 1318dae68fbaSMichal Koutný interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 13191abab1baSChen Ridong do not have any such application then you are completely fine leaving 13201abab1baSChen Ridong this option disabled. 13211abab1baSChen Ridong 13221abab1baSChen Ridong Say N if unsure. 13231abab1baSChen Ridong 13246bf024e6SJohannes Weinerconfig PROC_PID_CPUSET 13256bf024e6SJohannes Weiner bool "Include legacy /proc/<pid>/cpuset file" 1326dae68fbaSMichal Koutný depends on CPUSETS_V1 132789e9b9e0STejun Heo default y 132889e9b9e0STejun Heo 13296bf024e6SJohannes Weinerconfig CGROUP_DEVICE 13306bf024e6SJohannes Weiner bool "Device controller" 13316bf024e6SJohannes Weiner help 13326bf024e6SJohannes Weiner Provides a cgroup controller implementing whitelists for 13336bf024e6SJohannes Weiner devices which a process in the cgroup can mknod or open. 13346bf024e6SJohannes Weiner 13356bf024e6SJohannes Weinerconfig CGROUP_CPUACCT 13366bf024e6SJohannes Weiner bool "Simple CPU accounting controller" 13376bf024e6SJohannes Weiner help 13386bf024e6SJohannes Weiner Provides a simple controller for monitoring the 13396bf024e6SJohannes Weiner total CPU consumed by the tasks in a cgroup. 13406bf024e6SJohannes Weiner 13416bf024e6SJohannes Weinerconfig CGROUP_PERF 13426bf024e6SJohannes Weiner bool "Perf controller" 13436bf024e6SJohannes Weiner depends on PERF_EVENTS 13446bf024e6SJohannes Weiner help 13456bf024e6SJohannes Weiner This option extends the perf per-cpu mode to restrict monitoring 13466bf024e6SJohannes Weiner to threads which belong to the cgroup specified and run on the 13476546b19fSNamhyung Kim designated cpu. Or this can be used to have cgroup ID in samples 13486546b19fSNamhyung Kim so that it can monitor performance events among cgroups. 13496bf024e6SJohannes Weiner 13506bf024e6SJohannes Weiner Say N if unsure. 13516bf024e6SJohannes Weiner 135230070984SDaniel Mackconfig CGROUP_BPF 135330070984SDaniel Mack bool "Support for eBPF programs attached to cgroups" 1354483c4933SAndy Lutomirski depends on BPF_SYSCALL 1355483c4933SAndy Lutomirski select SOCK_CGROUP_DATA 135630070984SDaniel Mack help 135730070984SDaniel Mack Allow attaching eBPF programs to a cgroup using the bpf(2) 135830070984SDaniel Mack syscall command BPF_PROG_ATTACH. 135930070984SDaniel Mack 136030070984SDaniel Mack In which context these programs are accessed depends on the type 136130070984SDaniel Mack of attachment. For instance, programs that are attached using 136230070984SDaniel Mack BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 136330070984SDaniel Mack inet sockets. 136430070984SDaniel Mack 1365a72232eaSVipin Sharmaconfig CGROUP_MISC 1366a72232eaSVipin Sharma bool "Misc resource controller" 1367a72232eaSVipin Sharma default n 1368a72232eaSVipin Sharma help 1369a72232eaSVipin Sharma Provides a controller for miscellaneous resources on a host. 1370a72232eaSVipin Sharma 1371a72232eaSVipin Sharma Miscellaneous scalar resources are the resources on the host system 1372a72232eaSVipin Sharma which cannot be abstracted like the other cgroups. This controller 1373a72232eaSVipin Sharma tracks and limits the miscellaneous resources used by a process 1374a72232eaSVipin Sharma attached to a cgroup hierarchy. 1375a72232eaSVipin Sharma 1376a72232eaSVipin Sharma For more information, please check misc cgroup section in 1377a72232eaSVipin Sharma /Documentation/admin-guide/cgroup-v2.rst. 1378a72232eaSVipin Sharma 13796bf024e6SJohannes Weinerconfig CGROUP_DEBUG 138023b0be48SWaiman Long bool "Debug controller" 13816bf024e6SJohannes Weiner default n 138223b0be48SWaiman Long depends on DEBUG_KERNEL 13836bf024e6SJohannes Weiner help 13846bf024e6SJohannes Weiner This option enables a simple controller that exports 138523b0be48SWaiman Long debugging information about the cgroups framework. This 138623b0be48SWaiman Long controller is for control cgroup debugging only. Its 138723b0be48SWaiman Long interfaces are not stable. 13886bf024e6SJohannes Weiner 13896bf024e6SJohannes Weiner Say N. 13906bf024e6SJohannes Weiner 139173b35147SArnd Bergmannconfig SOCK_CGROUP_DATA 139273b35147SArnd Bergmann bool 139373b35147SArnd Bergmann default n 139473b35147SArnd Bergmann 139523964d2dSLi Zefanendif # CGROUPS 1396c077719bSKAMEZAWA Hiroyuki 13978dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 13986a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 13992813893fSIulia Manda depends on MULTIUSER 14006a108a14SDavid Rientjes default !EXPERT 1401c5289a69SPavel Emelyanov help 1402c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 1403c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 1404c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 1405c5289a69SPavel Emelyanov different namespaces. 1406c5289a69SPavel Emelyanov 14078dd2a82cSDaniel Lezcanoif NAMESPACES 14088dd2a82cSDaniel Lezcano 140958bfdd6dSPavel Emelyanovconfig UTS_NS 141058bfdd6dSPavel Emelyanov bool "UTS namespace" 141117a6d441SDaniel Lezcano default y 141258bfdd6dSPavel Emelyanov help 141358bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 141458bfdd6dSPavel Emelyanov uname() system call 141558bfdd6dSPavel Emelyanov 1416769071acSAndrei Vaginconfig TIME_NS 1417769071acSAndrei Vagin bool "TIME namespace" 1418769071acSAndrei Vagin default y 1419769071acSAndrei Vagin help 1420769071acSAndrei Vagin In this namespace boottime and monotonic clocks can be set. 1421769071acSAndrei Vagin The time will keep going with the same pace. 1422769071acSAndrei Vagin 14231b6c8928SThomas Weißschuhconfig TIME_NS_VDSO 14241b6c8928SThomas Weißschuh def_bool TIME_NS && GENERIC_GETTIMEOFDAY 14251b6c8928SThomas Weißschuh 1426ae5e1b22SPavel Emelyanovconfig IPC_NS 1427ae5e1b22SPavel Emelyanov bool "IPC namespace" 14288dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 142917a6d441SDaniel Lezcano default y 1430ae5e1b22SPavel Emelyanov help 1431ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 1432614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 1433ae5e1b22SPavel Emelyanov 1434aee16ce7SPavel Emelyanovconfig USER_NS 143519c92399SKees Cook bool "User namespace" 14365673a94cSEric W. Biederman default n 1437aee16ce7SPavel Emelyanov help 1438aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 1439aee16ce7SPavel Emelyanov to provide different user info for different servers. 1440e11f0ae3SEric W. Biederman 1441e11f0ae3SEric W. Biederman When user namespaces are enabled in the kernel it is 1442d886f4e4SJohannes Weiner recommended that the MEMCG option also be enabled and that 1443d886f4e4SJohannes Weiner user-space use the memory control groups to limit the amount 1444d886f4e4SJohannes Weiner of memory a memory unprivileged users can use. 1445e11f0ae3SEric W. Biederman 1446aee16ce7SPavel Emelyanov If unsure, say N. 1447aee16ce7SPavel Emelyanov 144874bd59bbSPavel Emelyanovconfig PID_NS 14499bd38c2cSDaniel Lezcano bool "PID Namespaces" 145017a6d441SDaniel Lezcano default y 145174bd59bbSPavel Emelyanov help 145212d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 1453692105b8SMatt LaPlante processes with the same pid as long as they are in different 145474bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 145574bd59bbSPavel Emelyanov 1456d6eb633fSMatt Helsleyconfig NET_NS 1457d6eb633fSMatt Helsley bool "Network namespace" 14588dd2a82cSDaniel Lezcano depends on NET 145917a6d441SDaniel Lezcano default y 1460d6eb633fSMatt Helsley help 1461d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 1462d6eb633fSMatt Helsley of the network stack. 1463d6eb633fSMatt Helsley 14648dd2a82cSDaniel Lezcanoendif # NAMESPACES 14658dd2a82cSDaniel Lezcano 14665cb366bbSAdrian Reberconfig CHECKPOINT_RESTORE 14675cb366bbSAdrian Reber bool "Checkpoint/restore support" 146830341ec9SRen Zhijie depends on PROC_FS 14695cb366bbSAdrian Reber select PROC_CHILDREN 1470bfe3911aSChris Wilson select KCMP 14715cb366bbSAdrian Reber default n 14725cb366bbSAdrian Reber help 14735cb366bbSAdrian Reber Enables additional kernel features in a sake of checkpoint/restore. 14745cb366bbSAdrian Reber In particular it adds auxiliary prctl codes to setup process text, 14755cb366bbSAdrian Reber data and heap segment sizes, and a few additional /proc filesystem 14765cb366bbSAdrian Reber entries. 14775cb366bbSAdrian Reber 14785cb366bbSAdrian Reber If unsure, say N here. 14795cb366bbSAdrian Reber 14805091faa4SMike Galbraithconfig SCHED_AUTOGROUP 14815091faa4SMike Galbraith bool "Automatic process group scheduling" 14825091faa4SMike Galbraith select CGROUPS 14835091faa4SMike Galbraith select CGROUP_SCHED 14845091faa4SMike Galbraith select FAIR_GROUP_SCHED 14855091faa4SMike Galbraith help 14865091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 14875091faa4SMike Galbraith automatically creating and populating task groups. This separation 14885091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 14895091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 14905091faa4SMike Galbraith upon task session. 14915091faa4SMike Galbraith 14927af37becSDaniel Lezcanoconfig RELAY 14937af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 149426b5679eSPeter Zijlstra select IRQ_WORK 14957af37becSDaniel Lezcano help 14967af37becSDaniel Lezcano This option enables support for relay interface support in 14977af37becSDaniel Lezcano certain file systems (such as debugfs). 14987af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 14997af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 15007af37becSDaniel Lezcano user space. 15017af37becSDaniel Lezcano 15027af37becSDaniel Lezcano If unsure, say N. 15037af37becSDaniel Lezcano 1504f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1505f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1506f991633dSDimitri Gorokhovik help 1507f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1508f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1509f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1510f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 15118c27ceffSMauro Carvalho Chehab etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1512f991633dSDimitri Gorokhovik 1513f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1514f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1515f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1516f991633dSDimitri Gorokhovik 1517f991633dSDimitri Gorokhovik If unsure say Y. 1518f991633dSDimitri Gorokhovik 1519c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1520c33df4eaSJean-Paul Saman 1521dbec4866SSam Ravnborgsource "usr/Kconfig" 1522dbec4866SSam Ravnborg 1523c33df4eaSJean-Paul Samanendif 1524c33df4eaSJean-Paul Saman 152576db5a27SMasami Hiramatsuconfig BOOT_CONFIG 152676db5a27SMasami Hiramatsu bool "Boot config support" 1527a2a9d67aSMasami Hiramatsu select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 152876db5a27SMasami Hiramatsu help 152976db5a27SMasami Hiramatsu Extra boot config allows system admin to pass a config file as 153076db5a27SMasami Hiramatsu complemental extension of kernel cmdline when booting. 15310947db01SMasami Hiramatsu The boot config file must be attached at the end of initramfs 153285c46b78SMasami Hiramatsu with checksum, size and magic word. 15330947db01SMasami Hiramatsu See <file:Documentation/admin-guide/bootconfig.rst> for details. 153476db5a27SMasami Hiramatsu 153576db5a27SMasami Hiramatsu If unsure, say Y. 153676db5a27SMasami Hiramatsu 1537b743852cSPaul E. McKenneyconfig BOOT_CONFIG_FORCE 1538b743852cSPaul E. McKenney bool "Force unconditional bootconfig processing" 1539b743852cSPaul E. McKenney depends on BOOT_CONFIG 15406ded8a28SPaul E. McKenney default y if BOOT_CONFIG_EMBED 1541b743852cSPaul E. McKenney help 1542b743852cSPaul E. McKenney With this Kconfig option set, BOOT_CONFIG processing is carried 1543b743852cSPaul E. McKenney out even when the "bootconfig" kernel-boot parameter is omitted. 1544b743852cSPaul E. McKenney In fact, with this Kconfig option set, there is no way to 1545b743852cSPaul E. McKenney make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1546b743852cSPaul E. McKenney parameters. 1547b743852cSPaul E. McKenney 1548b743852cSPaul E. McKenney If unsure, say N. 1549b743852cSPaul E. McKenney 1550a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED 1551a2a9d67aSMasami Hiramatsu bool "Embed bootconfig file in the kernel" 1552a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG 1553a2a9d67aSMasami Hiramatsu help 1554a2a9d67aSMasami Hiramatsu Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1555a2a9d67aSMasami Hiramatsu kernel. Usually, the bootconfig file is loaded with the initrd 1556a2a9d67aSMasami Hiramatsu image. But if the system doesn't support initrd, this option will 1557a2a9d67aSMasami Hiramatsu help you by embedding a bootconfig file while building the kernel. 1558a2a9d67aSMasami Hiramatsu 1559a2a9d67aSMasami Hiramatsu If unsure, say N. 1560a2a9d67aSMasami Hiramatsu 1561a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED_FILE 1562a2a9d67aSMasami Hiramatsu string "Embedded bootconfig file path" 1563a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG_EMBED 1564a2a9d67aSMasami Hiramatsu help 1565a2a9d67aSMasami Hiramatsu Specify a bootconfig file which will be embedded to the kernel. 1566a2a9d67aSMasami Hiramatsu This bootconfig will be used if there is no initrd or no other 1567a2a9d67aSMasami Hiramatsu bootconfig in the initrd. 1568a2a9d67aSMasami Hiramatsu 1569032a7302SDouglas Andersonconfig CMDLINE_LOG_WRAP_IDEAL_LEN 1570032a7302SDouglas Anderson int "Length to try to wrap the cmdline when logged at boot" 1571032a7302SDouglas Anderson default 1021 1572032a7302SDouglas Anderson range 0 1021 1573032a7302SDouglas Anderson help 1574032a7302SDouglas Anderson At boot time, the kernel command line is logged to the console. 1575032a7302SDouglas Anderson The log message will start with the prefix "Kernel command line: ". 1576032a7302SDouglas Anderson The log message will attempt to be wrapped (split into multiple log 1577032a7302SDouglas Anderson messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1578032a7302SDouglas Anderson If wrapping happens, each log message will start with the prefix and 1579032a7302SDouglas Anderson all but the last message will end with " \". Messages may exceed the 1580032a7302SDouglas Anderson ideal length if a place to wrap isn't found before the specified 1581032a7302SDouglas Anderson number of characters. 1582032a7302SDouglas Anderson 1583032a7302SDouglas Anderson A value of 0 disables wrapping, though be warned that the maximum 1584032a7302SDouglas Anderson length of a log message (1021 characters) may cause the cmdline to 1585032a7302SDouglas Anderson be truncated. 1586032a7302SDouglas Anderson 15871274aea1SDavid Disseldorpconfig INITRAMFS_PRESERVE_MTIME 15881274aea1SDavid Disseldorp bool "Preserve cpio archive mtimes in initramfs" 158974792608SGeert Uytterhoeven depends on BLK_DEV_INITRD 15901274aea1SDavid Disseldorp default y 15911274aea1SDavid Disseldorp help 15921274aea1SDavid Disseldorp Each entry in an initramfs cpio archive carries an mtime value. When 15931274aea1SDavid Disseldorp enabled, extracted cpio items take this mtime, with directory mtime 15941274aea1SDavid Disseldorp setting deferred until after creation of any child entries. 15951274aea1SDavid Disseldorp 15961274aea1SDavid Disseldorp If unsure, say Y. 15971274aea1SDavid Disseldorp 159883c0b272SDavid Disseldorpconfig INITRAMFS_TEST 159983c0b272SDavid Disseldorp bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 160083c0b272SDavid Disseldorp depends on BLK_DEV_INITRD && KUNIT=y 160183c0b272SDavid Disseldorp default KUNIT_ALL_TESTS 160283c0b272SDavid Disseldorp help 160383c0b272SDavid Disseldorp Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 160483c0b272SDavid Disseldorp 1605877417e6SArnd Bergmannchoice 1606877417e6SArnd Bergmann prompt "Compiler optimization level" 16072cc3ce24SUlf Magnusson default CC_OPTIMIZE_FOR_PERFORMANCE 1608877417e6SArnd Bergmann 1609877417e6SArnd Bergmannconfig CC_OPTIMIZE_FOR_PERFORMANCE 161015f5db60SMasahiro Yamada bool "Optimize for performance (-O2)" 1611877417e6SArnd Bergmann help 1612877417e6SArnd Bergmann This is the default optimization level for the kernel, building 1613877417e6SArnd Bergmann with the "-O2" compiler flag for best performance and most 1614877417e6SArnd Bergmann helpful compile-time warnings. 1615877417e6SArnd Bergmann 1616c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 161715f5db60SMasahiro Yamada bool "Optimize for size (-Os)" 1618c45b4f1fSLinus Torvalds help 1619ce3b487fSMasahiro Yamada Choosing this option will pass "-Os" to your compiler resulting 1620ce3b487fSMasahiro Yamada in a smaller kernel. 1621c45b4f1fSLinus Torvalds 1622877417e6SArnd Bergmannendchoice 1623877417e6SArnd Bergmann 16245d20ee31SNicholas Pigginconfig HAVE_LD_DEAD_CODE_DATA_ELIMINATION 16255d20ee31SNicholas Piggin bool 16265d20ee31SNicholas Piggin help 16275d20ee31SNicholas Piggin This requires that the arch annotates or otherwise protects 16285d20ee31SNicholas Piggin its external entry points from being discarded. Linker scripts 16295d20ee31SNicholas Piggin must also merge .text.*, .data.*, and .bss.* correctly into 16305d20ee31SNicholas Piggin output sections. Care must be taken not to pull in unrelated 16315d20ee31SNicholas Piggin sections (e.g., '.text.init'). Typically '.' in section names 16325d20ee31SNicholas Piggin is used to distinguish them from label names / C identifiers. 16335d20ee31SNicholas Piggin 16345d20ee31SNicholas Pigginconfig LD_DEAD_CODE_DATA_ELIMINATION 16355d20ee31SNicholas Piggin bool "Dead code and data elimination (EXPERIMENTAL)" 16365d20ee31SNicholas Piggin depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 16375d20ee31SNicholas Piggin depends on EXPERT 1638e85d1d65SMasahiro Yamada depends on $(cc-option,-ffunction-sections -fdata-sections) 1639e85d1d65SMasahiro Yamada depends on $(ld-option,--gc-sections) 16405d20ee31SNicholas Piggin help 16418b9d2712SMasahiro Yamada Enable this if you want to do dead code and data elimination with 16428b9d2712SMasahiro Yamada the linker by compiling with -ffunction-sections -fdata-sections, 16438b9d2712SMasahiro Yamada and linking with --gc-sections. 16445d20ee31SNicholas Piggin 16455d20ee31SNicholas Piggin This can reduce on disk and in-memory size of the kernel 16465d20ee31SNicholas Piggin code and static data, particularly for small configs and 16475d20ee31SNicholas Piggin on small systems. This has the possibility of introducing 16485d20ee31SNicholas Piggin silently broken kernel if the required annotations are not 16495d20ee31SNicholas Piggin present. This option is not well tested yet, so use at your 16505d20ee31SNicholas Piggin own risk. 16515d20ee31SNicholas Piggin 165259612b24SNathan Chancellorconfig LD_ORPHAN_WARN 165359612b24SNathan Chancellor def_bool y 165459612b24SNathan Chancellor depends on ARCH_WANT_LD_ORPHAN_WARN 165559612b24SNathan Chancellor depends on $(ld-option,--orphan-handling=warn) 1656e1789d7cSXin Li depends on $(ld-option,--orphan-handling=error) 1657e1789d7cSXin Li 1658e1789d7cSXin Liconfig LD_ORPHAN_WARN_LEVEL 1659e1789d7cSXin Li string 1660e1789d7cSXin Li depends on LD_ORPHAN_WARN 1661e1789d7cSXin Li default "error" if WERROR 1662e1789d7cSXin Li default "warn" 166359612b24SNathan Chancellor 16640847062aSRandy Dunlapconfig SYSCTL 16650847062aSRandy Dunlap bool 16660847062aSRandy Dunlap 1667657a5209SMike Frysingerconfig HAVE_UID16 1668657a5209SMike Frysinger bool 1669657a5209SMike Frysinger 1670657a5209SMike Frysingerconfig SYSCTL_EXCEPTION_TRACE 1671657a5209SMike Frysinger bool 1672657a5209SMike Frysinger help 1673657a5209SMike Frysinger Enable support for /proc/sys/debug/exception-trace. 1674657a5209SMike Frysinger 1675657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_NO_WARN 1676657a5209SMike Frysinger bool 1677657a5209SMike Frysinger help 1678657a5209SMike Frysinger Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1679657a5209SMike Frysinger Allows arch to define/use @no_unaligned_warning to possibly warn 1680657a5209SMike Frysinger about unaligned access emulation going on under the hood. 1681657a5209SMike Frysinger 1682657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_ALLOW 1683657a5209SMike Frysinger bool 1684657a5209SMike Frysinger help 1685657a5209SMike Frysinger Enable support for /proc/sys/kernel/unaligned-trap 1686657a5209SMike Frysinger Allows arches to define/use @unaligned_enabled to runtime toggle 1687657a5209SMike Frysinger the unaligned access emulation. 1688657a5209SMike Frysinger see arch/parisc/kernel/unaligned.c for reference 1689657a5209SMike Frysinger 1690c443279aSChristian Braunerconfig SYSFS_SYSCALL 1691c443279aSChristian Brauner bool "Sysfs syscall support" 1692c443279aSChristian Brauner default n 1693c443279aSChristian Brauner help 1694c443279aSChristian Brauner sys_sysfs is an obsolete system call no longer supported in libc. 1695c443279aSChristian Brauner Note that disabling this option is more secure but might break 1696c443279aSChristian Brauner compatibility with some systems. 1697c443279aSChristian Brauner 1698c443279aSChristian Brauner If unsure say N here. 1699c443279aSChristian Brauner 1700657a5209SMike Frysingerconfig HAVE_PCSPKR_PLATFORM 1701657a5209SMike Frysinger bool 1702657a5209SMike Frysinger 17036a108a14SDavid Rientjesmenuconfig EXPERT 17046a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1705f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1706f505c553SJosh Triplett select DEBUG_KERNEL 17071da177e4SLinus Torvalds help 17081da177e4SLinus Torvalds This option allows certain base kernel options and settings 17091da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 17101da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 17111da177e4SLinus Torvalds Only use this if you really know what you are doing. 17121da177e4SLinus Torvalds 1713ae81f9e3SChuck Ebbertconfig UID16 17146a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 17152813893fSIulia Manda depends on HAVE_UID16 && MULTIUSER 1716ae81f9e3SChuck Ebbert default y 1717ae81f9e3SChuck Ebbert help 1718ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1719ae81f9e3SChuck Ebbert 17202813893fSIulia Mandaconfig MULTIUSER 17212813893fSIulia Manda bool "Multiple users, groups and capabilities support" if EXPERT 17222813893fSIulia Manda default y 17232813893fSIulia Manda help 17242813893fSIulia Manda This option enables support for non-root users, groups and 17252813893fSIulia Manda capabilities. 17262813893fSIulia Manda 17272813893fSIulia Manda If you say N here, all processes will run with UID 0, GID 0, and all 17282813893fSIulia Manda possible capabilities. Saying N here also compiles out support for 17292813893fSIulia Manda system calls related to UIDs, GIDs, and capabilities, such as setuid, 17302813893fSIulia Manda setgid, and capset. 17312813893fSIulia Manda 17322813893fSIulia Manda If unsure, say Y here. 17332813893fSIulia Manda 1734f6187769SFabian Frederickconfig SGETMASK_SYSCALL 1735f6187769SFabian Frederick bool "sgetmask/ssetmask syscalls support" if EXPERT 1736cd14b018SMasahiro Yamada default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1737a7f7f624SMasahiro Yamada help 1738f6187769SFabian Frederick sys_sgetmask and sys_ssetmask are obsolete system calls 1739f6187769SFabian Frederick no longer supported in libc but still enabled by default in some 1740f6187769SFabian Frederick architectures. 1741f6187769SFabian Frederick 1742f6187769SFabian Frederick If unsure, leave the default option here. 1743f6187769SFabian Frederick 1744d1b069f5SRandy Dunlapconfig FHANDLE 1745d1b069f5SRandy Dunlap bool "open by fhandle syscalls" if EXPERT 1746d1b069f5SRandy Dunlap select EXPORTFS 1747d1b069f5SRandy Dunlap default y 1748d1b069f5SRandy Dunlap help 1749d1b069f5SRandy Dunlap If you say Y here, a user level program will be able to map 1750d1b069f5SRandy Dunlap file names to handle and then later use the handle for 1751d1b069f5SRandy Dunlap different file system operations. This is useful in implementing 1752d1b069f5SRandy Dunlap userspace file servers, which now track files using handles instead 1753d1b069f5SRandy Dunlap of names. The handle would remain the same even if file names 1754d1b069f5SRandy Dunlap get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1755d1b069f5SRandy Dunlap syscalls. 1756d1b069f5SRandy Dunlap 1757baa73d9eSNicolas Pitreconfig POSIX_TIMERS 1758baa73d9eSNicolas Pitre bool "Posix Clocks & timers" if EXPERT 1759baa73d9eSNicolas Pitre default y 1760baa73d9eSNicolas Pitre help 1761baa73d9eSNicolas Pitre This includes native support for POSIX timers to the kernel. 1762baa73d9eSNicolas Pitre Some embedded systems have no use for them and therefore they 1763baa73d9eSNicolas Pitre can be configured out to reduce the size of the kernel image. 1764baa73d9eSNicolas Pitre 1765baa73d9eSNicolas Pitre When this option is disabled, the following syscalls won't be 1766baa73d9eSNicolas Pitre available: timer_create, timer_gettime: timer_getoverrun, 1767baa73d9eSNicolas Pitre timer_settime, timer_delete, clock_adjtime, getitimer, 1768baa73d9eSNicolas Pitre setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1769baa73d9eSNicolas Pitre clock_getres and clock_nanosleep syscalls will be limited to 1770baa73d9eSNicolas Pitre CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1771baa73d9eSNicolas Pitre 1772baa73d9eSNicolas Pitre If unsure say y. 1773baa73d9eSNicolas Pitre 1774d59745ceSMatt Mackallconfig PRINTK 1775d59745ceSMatt Mackall default y 17766a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 177774876a98SFrederic Weisbecker select IRQ_WORK 1778d59745ceSMatt Mackall help 1779d59745ceSMatt Mackall This option enables normal printk support. Removing it 1780d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1781d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1782d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1783d59745ceSMatt Mackall strongly discouraged. 1784d59745ceSMatt Mackall 17855ea2bcdfSThomas Weißschuhconfig PRINTK_RINGBUFFER_KUNIT_TEST 17865ea2bcdfSThomas Weißschuh tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 17875ea2bcdfSThomas Weißschuh depends on PRINTK && KUNIT 17885ea2bcdfSThomas Weißschuh default KUNIT_ALL_TESTS 17895ea2bcdfSThomas Weißschuh help 17905ea2bcdfSThomas Weißschuh This builds the printk ringbuffer KUnit test suite. 17915ea2bcdfSThomas Weißschuh 17925ea2bcdfSThomas Weißschuh For more information on KUnit and unit tests in general, please refer 17935ea2bcdfSThomas Weißschuh to the KUnit documentation. 17945ea2bcdfSThomas Weißschuh 17955ea2bcdfSThomas Weißschuh If unsure, say N. 17965ea2bcdfSThomas Weißschuh 1797c8538a7aSMatt Mackallconfig BUG 17986a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1799c8538a7aSMatt Mackall default y 1800c8538a7aSMatt Mackall help 1801c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1802c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1803c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1804c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1805c8538a7aSMatt Mackall Just say Y. 1806c8538a7aSMatt Mackall 1807708e9a79SMatt Mackallconfig ELF_CORE 1808046d662fSAlex Kelly depends on COREDUMP 1809708e9a79SMatt Mackall default y 18106a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1811708e9a79SMatt Mackall help 1812708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1813708e9a79SMatt Mackall 18148761f1abSRalf Baechle 1815e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 18166a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 18178761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 181815f304b6SRalf Baechle select I8253_LOCK 1819e5e1d3cbSStas Sergeev default y 1820e5e1d3cbSStas Sergeev help 1821e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1822e5e1d3cbSStas Sergeev support, saving some memory. 1823e5e1d3cbSStas Sergeev 182427021649SYoann Congalconfig BASE_SMALL 182527021649SYoann Congal bool "Enable smaller-sized data structures for core" if EXPERT 18261da177e4SLinus Torvalds help 182727021649SYoann Congal Enabling this option reduces the size of miscellaneous core 18281da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 18291da177e4SLinus Torvalds but may reduce performance. 18301da177e4SLinus Torvalds 18311da177e4SLinus Torvaldsconfig FUTEX 18326a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 18333f2bedabSArnd Bergmann depends on !(SPARC32 && SMP) 18341da177e4SLinus Torvalds default y 1835bc2eecd7SNicolas Pitre imply RT_MUTEXES 18361da177e4SLinus Torvalds help 18371da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18381da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 18391da177e4SLinus Torvalds run glibc-based applications correctly. 18401da177e4SLinus Torvalds 1841bc2eecd7SNicolas Pitreconfig FUTEX_PI 1842bc2eecd7SNicolas Pitre bool 1843bc2eecd7SNicolas Pitre depends on FUTEX && RT_MUTEXES 1844bc2eecd7SNicolas Pitre default y 1845bc2eecd7SNicolas Pitre 184680367ad0SSebastian Andrzej Siewiorconfig FUTEX_PRIVATE_HASH 184780367ad0SSebastian Andrzej Siewior bool 184880367ad0SSebastian Andrzej Siewior depends on FUTEX && !BASE_SMALL && MMU 184980367ad0SSebastian Andrzej Siewior default y 185080367ad0SSebastian Andrzej Siewior 1851c042c505SPeter Zijlstraconfig FUTEX_MPOL 1852c042c505SPeter Zijlstra bool 1853c042c505SPeter Zijlstra depends on FUTEX && NUMA 1854c042c505SPeter Zijlstra default y 1855c042c505SPeter Zijlstra 1856042df0c1SThomas Gleixnerconfig HAVE_FUTEX_ROBUST_UNLOCK 1857042df0c1SThomas Gleixner bool 1858042df0c1SThomas Gleixner 1859042df0c1SThomas Gleixnerconfig FUTEX_ROBUST_UNLOCK 1860042df0c1SThomas Gleixner def_bool FUTEX && HAVE_GENERIC_VDSO && GENERIC_IRQ_ENTRY && RSEQ && HAVE_FUTEX_ROBUST_UNLOCK 1861042df0c1SThomas Gleixner 18621da177e4SLinus Torvaldsconfig EPOLL 18636a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 18641da177e4SLinus Torvalds default y 18651da177e4SLinus Torvalds help 18661da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18671da177e4SLinus Torvalds support for epoll family of system calls. 18681da177e4SLinus Torvalds 1869fba2afaaSDavide Libenziconfig SIGNALFD 18706a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1871fba2afaaSDavide Libenzi default y 1872fba2afaaSDavide Libenzi help 1873fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1874fba2afaaSDavide Libenzi on a file descriptor. 1875fba2afaaSDavide Libenzi 1876fba2afaaSDavide Libenzi If unsure, say Y. 1877fba2afaaSDavide Libenzi 1878b215e283SDavide Libenziconfig TIMERFD 18796a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1880b215e283SDavide Libenzi default y 1881b215e283SDavide Libenzi help 1882b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1883b215e283SDavide Libenzi events on a file descriptor. 1884b215e283SDavide Libenzi 1885b215e283SDavide Libenzi If unsure, say Y. 1886b215e283SDavide Libenzi 1887e1ad7468SDavide Libenziconfig EVENTFD 18886a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1889e1ad7468SDavide Libenzi default y 1890e1ad7468SDavide Libenzi help 1891e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1892e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1893e1ad7468SDavide Libenzi 1894e1ad7468SDavide Libenzi If unsure, say Y. 1895e1ad7468SDavide Libenzi 18961da177e4SLinus Torvaldsconfig SHMEM 18976a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 18981da177e4SLinus Torvalds default y 18991da177e4SLinus Torvalds depends on MMU 19001da177e4SLinus Torvalds help 19011da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 19021da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 19031da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 19041da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 19051da177e4SLinus Torvalds which may be appropriate on small systems without swap. 19061da177e4SLinus Torvalds 1907ebf3f09cSThomas Petazzoniconfig AIO 19086a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1909ebf3f09cSThomas Petazzoni default y 1910ebf3f09cSThomas Petazzoni help 1911ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1912ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1913ebf3f09cSThomas Petazzoni this option saves about 7k. 1914ebf3f09cSThomas Petazzoni 19152b188cc1SJens Axboeconfig IO_URING 19162b188cc1SJens Axboe bool "Enable IO uring support" if EXPERT 1917561fb04aSJens Axboe select IO_WQ 19182b188cc1SJens Axboe default y 19192b188cc1SJens Axboe help 19202b188cc1SJens Axboe This option enables support for the io_uring interface, enabling 19212b188cc1SJens Axboe applications to submit and complete IO through submission and 19222b188cc1SJens Axboe completion rings that are shared between the kernel and application. 19232b188cc1SJens Axboe 19241802656eSJens Axboeconfig GCOV_PROFILE_URING 19251802656eSJens Axboe bool "Enable GCOV profiling on the io_uring subsystem" 1926d1fbe1ebSRandy Dunlap depends on IO_URING && GCOV_KERNEL 19271802656eSJens Axboe help 19281802656eSJens Axboe Enable GCOV profiling on the io_uring subsystem, to facilitate 19291802656eSJens Axboe code coverage testing. 19301802656eSJens Axboe 19311802656eSJens Axboe If unsure, say N. 19321802656eSJens Axboe 19331802656eSJens Axboe Note that this will have a negative impact on the performance of 19341802656eSJens Axboe the io_uring subsystem, hence this should only be enabled for 19351802656eSJens Axboe specific test purposes. 19361802656eSJens Axboe 19373a0ae385SPavel Begunkovconfig IO_URING_MOCK_FILE 19383a0ae385SPavel Begunkov tristate "Enable io_uring mock files (Experimental)" if EXPERT 19393a0ae385SPavel Begunkov default n 19403a0ae385SPavel Begunkov depends on IO_URING 19413a0ae385SPavel Begunkov help 19429e7dc228SJ. Neuschäfer Enable mock files for io_uring subsystem testing. The ABI might 19433a0ae385SPavel Begunkov still change, so it's still experimental and should only be enabled 19443a0ae385SPavel Begunkov for specific test purposes. 19453a0ae385SPavel Begunkov 19463a0ae385SPavel Begunkov If unsure, say N. 19473a0ae385SPavel Begunkov 1948d3ac21caSJosh Triplettconfig ADVISE_SYSCALLS 1949d3ac21caSJosh Triplett bool "Enable madvise/fadvise syscalls" if EXPERT 1950d3ac21caSJosh Triplett default y 1951d3ac21caSJosh Triplett help 1952d3ac21caSJosh Triplett This option enables the madvise and fadvise syscalls, used by 1953d3ac21caSJosh Triplett applications to advise the kernel about their future memory or file 1954d3ac21caSJosh Triplett usage, improving performance. If building an embedded system where no 1955d3ac21caSJosh Triplett applications use these syscalls, you can disable this option to save 1956d3ac21caSJosh Triplett space. 1957d3ac21caSJosh Triplett 19585b25b13aSMathieu Desnoyersconfig MEMBARRIER 19595b25b13aSMathieu Desnoyers bool "Enable membarrier() system call" if EXPERT 19605b25b13aSMathieu Desnoyers default y 19615b25b13aSMathieu Desnoyers help 19625b25b13aSMathieu Desnoyers Enable the membarrier() system call that allows issuing memory 19635b25b13aSMathieu Desnoyers barriers across all running threads, which can be used to distribute 19645b25b13aSMathieu Desnoyers the cost of user-space memory barriers asymmetrically by transforming 19655b25b13aSMathieu Desnoyers pairs of memory barriers into pairs consisting of membarrier() and a 19665b25b13aSMathieu Desnoyers compiler barrier. 19675b25b13aSMathieu Desnoyers 19685b25b13aSMathieu Desnoyers If unsure, say Y. 19695b25b13aSMathieu Desnoyers 1970a751ea34SRandy Dunlapconfig KCMP 1971a751ea34SRandy Dunlap bool "Enable kcmp() system call" if EXPERT 1972a751ea34SRandy Dunlap help 1973a751ea34SRandy Dunlap Enable the kernel resource comparison system call. It provides 1974a751ea34SRandy Dunlap user-space with the ability to compare two processes to see if they 1975a751ea34SRandy Dunlap share a common resource, such as a file descriptor or even virtual 1976a751ea34SRandy Dunlap memory space. 1977a751ea34SRandy Dunlap 1978a751ea34SRandy Dunlap If unsure, say N. 1979a751ea34SRandy Dunlap 1980a751ea34SRandy Dunlapconfig RSEQ 1981a751ea34SRandy Dunlap bool "Enable rseq() system call" if EXPERT 1982a751ea34SRandy Dunlap default y 1983a751ea34SRandy Dunlap depends on HAVE_RSEQ 1984a751ea34SRandy Dunlap select MEMBARRIER 1985a751ea34SRandy Dunlap help 1986a751ea34SRandy Dunlap Enable the restartable sequences system call. It provides a 1987a751ea34SRandy Dunlap user-space cache for the current CPU number value, which 1988a751ea34SRandy Dunlap speeds up getting the current CPU number from user-space, 1989a751ea34SRandy Dunlap as well as an ABI to speed up user-space operations on 1990a751ea34SRandy Dunlap per-CPU data. 1991a751ea34SRandy Dunlap 1992a751ea34SRandy Dunlap If unsure, say Y. 1993a751ea34SRandy Dunlap 1994d7a5da7aSThomas Gleixnerconfig RSEQ_SLICE_EXTENSION 1995d7a5da7aSThomas Gleixner bool "Enable rseq-based time slice extension mechanism" 1996d7a5da7aSThomas Gleixner depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 1997d7a5da7aSThomas Gleixner help 1998d7a5da7aSThomas Gleixner Allows userspace to request a limited time slice extension when 1999d7a5da7aSThomas Gleixner returning from an interrupt to user space via the RSEQ shared 2000d7a5da7aSThomas Gleixner data ABI. If granted, that allows to complete a critical section, 2001d7a5da7aSThomas Gleixner so that other threads are not stuck on a conflicted resource, 2002d7a5da7aSThomas Gleixner while the task is scheduled out. 2003d7a5da7aSThomas Gleixner 2004d7a5da7aSThomas Gleixner If unsure, say N. 2005d7a5da7aSThomas Gleixner 200654129104SThomas Gleixnerconfig RSEQ_STATS 200754129104SThomas Gleixner default n 200854129104SThomas Gleixner bool "Enable lightweight statistics of restartable sequences" if EXPERT 200954129104SThomas Gleixner depends on RSEQ && DEBUG_FS 201054129104SThomas Gleixner help 201154129104SThomas Gleixner Enable lightweight counters which expose information about the 201254129104SThomas Gleixner frequency of RSEQ operations via debugfs. Mostly interesting for 201354129104SThomas Gleixner kernel debugging or performance analysis. While lightweight it's 201454129104SThomas Gleixner still adding code into the user/kernel mode transitions. 201554129104SThomas Gleixner 201654129104SThomas Gleixner If unsure, say N. 201754129104SThomas Gleixner 20189c37cb6eSThomas Gleixnerconfig RSEQ_DEBUG_DEFAULT_ENABLE 20199c37cb6eSThomas Gleixner default n 20209c37cb6eSThomas Gleixner bool "Enable restartable sequences debug mode by default" if EXPERT 20219c37cb6eSThomas Gleixner depends on RSEQ 20229c37cb6eSThomas Gleixner help 20239c37cb6eSThomas Gleixner This enables the static branch for debug mode of restartable 20249c37cb6eSThomas Gleixner sequences. 20259c37cb6eSThomas Gleixner 20269c37cb6eSThomas Gleixner This also can be controlled on the kernel command line via the 20279c37cb6eSThomas Gleixner command line parameter "rseq_debug=0/1" and through debugfs. 20289c37cb6eSThomas Gleixner 20299c37cb6eSThomas Gleixner If unsure, say N. 20309c37cb6eSThomas Gleixner 2031a751ea34SRandy Dunlapconfig DEBUG_RSEQ 2032a751ea34SRandy Dunlap default n 2033a751ea34SRandy Dunlap bool "Enable debugging of rseq() system call" if EXPERT 20343db6b38dSThomas Gleixner depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 20359c37cb6eSThomas Gleixner select RSEQ_DEBUG_DEFAULT_ENABLE 2036a751ea34SRandy Dunlap help 2037a751ea34SRandy Dunlap Enable extra debugging checks for the rseq system call. 2038a751ea34SRandy Dunlap 2039a751ea34SRandy Dunlap If unsure, say N. 2040a751ea34SRandy Dunlap 2041a751ea34SRandy Dunlapconfig CACHESTAT_SYSCALL 2042a751ea34SRandy Dunlap bool "Enable cachestat() system call" if EXPERT 2043a751ea34SRandy Dunlap default y 2044a751ea34SRandy Dunlap help 2045a751ea34SRandy Dunlap Enable the cachestat system call, which queries the page cache 2046a751ea34SRandy Dunlap statistics of a file (number of cached pages, dirty pages, 2047a751ea34SRandy Dunlap pages marked for writeback, (recently) evicted pages). 2048a751ea34SRandy Dunlap 2049a751ea34SRandy Dunlap If unsure say Y here. 2050a751ea34SRandy Dunlap 2051d1b069f5SRandy Dunlapconfig KALLSYMS 2052d1b069f5SRandy Dunlap bool "Load all symbols for debugging/ksymoops" if EXPERT 2053d1b069f5SRandy Dunlap default y 2054d1b069f5SRandy Dunlap help 2055d1b069f5SRandy Dunlap Say Y here to let the kernel print out symbolic crash information and 2056d1b069f5SRandy Dunlap symbolic stack backtraces. This increases the size of the kernel 2057d1b069f5SRandy Dunlap somewhat, as all symbols have to be loaded into the kernel image. 2058d1b069f5SRandy Dunlap 205930f3bb09SZhen Leiconfig KALLSYMS_SELFTEST 206030f3bb09SZhen Lei bool "Test the basic functions and performance of kallsyms" 206130f3bb09SZhen Lei depends on KALLSYMS 206230f3bb09SZhen Lei default n 206330f3bb09SZhen Lei help 206430f3bb09SZhen Lei Test the basic functions and performance of some interfaces, such as 206530f3bb09SZhen Lei kallsyms_lookup_name. It also calculates the compression rate of the 206630f3bb09SZhen Lei kallsyms compression algorithm for the current symbol set. 206730f3bb09SZhen Lei 206830f3bb09SZhen Lei Start self-test automatically after system startup. Suggest executing 206930f3bb09SZhen Lei "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 207030f3bb09SZhen Lei displayed in the last line, indicating that the test is complete. 207130f3bb09SZhen Lei 2072d1b069f5SRandy Dunlapconfig KALLSYMS_ALL 2073d1b069f5SRandy Dunlap bool "Include all symbols in kallsyms" 2074d1b069f5SRandy Dunlap depends on DEBUG_KERNEL && KALLSYMS 2075d1b069f5SRandy Dunlap help 2076d1b069f5SRandy Dunlap Normally kallsyms only contains the symbols of functions for nicer 2077d1b069f5SRandy Dunlap OOPS messages and backtraces (i.e., symbols from the text and inittext 2078bdf0fe33SBaruch Siach sections). This is sufficient for most cases. And only if you want to 2079bdf0fe33SBaruch Siach enable kernel live patching, or other less common use cases (e.g., 2080bdf0fe33SBaruch Siach when a debugger is used) all symbols are required (i.e., names of 2081bdf0fe33SBaruch Siach variables from the data sections, etc). 2082d1b069f5SRandy Dunlap 2083d1b069f5SRandy Dunlap This option makes sure that all symbols are loaded into the kernel 2084d1b069f5SRandy Dunlap image (i.e., symbols from all sections) in cost of increased kernel 2085d1b069f5SRandy Dunlap size (depending on the kernel configuration, it may be 300KiB or 2086d1b069f5SRandy Dunlap something like this). 2087d1b069f5SRandy Dunlap 2088bdf0fe33SBaruch Siach Say N unless you really need all symbols, or kernel live patching. 2089d1b069f5SRandy Dunlap 2090d1b069f5SRandy Dunlap# end of the "standard kernel features (expert users)" menu 2091d1b069f5SRandy Dunlap 20923ccfebedSMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_CALLBACKS 20933ccfebedSMathieu Desnoyers bool 20943ccfebedSMathieu Desnoyers 209570216e18SMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_SYNC_CORE 209670216e18SMathieu Desnoyers bool 209770216e18SMathieu Desnoyers 20985796d396SJeff Xuconfig ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 20995796d396SJeff Xu bool 21005796d396SJeff Xu help 21015796d396SJeff Xu Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 21025796d396SJeff Xu 21035796d396SJeff Xu A 64-bit kernel is required for the memory sealing feature. 21045796d396SJeff Xu No specific hardware features from the CPU are needed. 21055796d396SJeff Xu 21065796d396SJeff Xu To enable this feature, the architecture needs to update their 21075796d396SJeff Xu special mappings calls to include the sealing flag and confirm 21085796d396SJeff Xu that it doesn't unmap/remap system mappings during the life 21095796d396SJeff Xu time of the process. The existence of this flag for an architecture 21105796d396SJeff Xu implies that it does not require the remapping of the system 21115796d396SJeff Xu mappings during process lifetime, so sealing these mappings is safe 21125796d396SJeff Xu from a kernel perspective. 21135796d396SJeff Xu 21145796d396SJeff Xu After the architecture enables this, a distribution can set 21155796d396SJeff Xu CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 21165796d396SJeff Xu 21175796d396SJeff Xu For complete descriptions of memory sealing, please see 21185796d396SJeff Xu Documentation/userspace-api/mseal.rst 21195796d396SJeff Xu 2120cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 21210793a61dSThomas Gleixner bool 2122018df72dSMike Frysinger help 2123018df72dSMike Frysinger See tools/perf/design.txt for details. 21240793a61dSThomas Gleixner 21252aef6f30SSean Christophersonconfig GUEST_PERF_EVENTS 21262aef6f30SSean Christopherson bool 21272aef6f30SSean Christopherson depends on HAVE_PERF_EVENTS 21282aef6f30SSean Christopherson 2129eff95e17SKan Liangconfig PERF_GUEST_MEDIATED_PMU 2130eff95e17SKan Liang bool 2131eff95e17SKan Liang depends on GUEST_PERF_EVENTS 2132eff95e17SKan Liang 2133906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 2134906010b2SPeter Zijlstra bool 2135906010b2SPeter Zijlstra help 2136906010b2SPeter Zijlstra See tools/perf/design.txt for details 2137906010b2SPeter Zijlstra 213857c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 21390793a61dSThomas Gleixner 2140cdd6c482SIngo Molnarconfig PERF_EVENTS 214157c0c15bSIngo Molnar bool "Kernel performance events and counters" 2142392d65a9SRobert Richter default y if PROFILING 2143cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 2144e360adbeSPeter Zijlstra select IRQ_WORK 21450793a61dSThomas Gleixner help 214657c0c15bSIngo Molnar Enable kernel support for various performance events provided 214757c0c15bSIngo Molnar by software and hardware. 21480793a61dSThomas Gleixner 2149dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 215057c0c15bSIngo Molnar use of generic tracepoints. 215157c0c15bSIngo Molnar 215257c0c15bSIngo Molnar Most modern CPUs support performance events via performance 215357c0c15bSIngo Molnar counter registers. These registers count the number of certain 21540793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 21550793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 21560793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 21570793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 21580793a61dSThomas Gleixner used to profile the code that runs on that CPU. 21590793a61dSThomas Gleixner 216057c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 2161dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 216257c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 21630793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 21640793a61dSThomas Gleixner capabilities on top of those. 21650793a61dSThomas Gleixner 21660793a61dSThomas Gleixner Say Y if unsure. 21670793a61dSThomas Gleixner 2168906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 2169906010b2SPeter Zijlstra default n 2170906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 2171cb307113SMichael Ellerman depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2172906010b2SPeter Zijlstra select PERF_USE_VMALLOC 2173906010b2SPeter Zijlstra help 2174906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 2175906010b2SPeter Zijlstra 2176906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 2177906010b2SPeter Zijlstra that don't require it. 2178906010b2SPeter Zijlstra 2179906010b2SPeter Zijlstra Say N if unsure. 2180906010b2SPeter Zijlstra 21810793a61dSThomas Gleixnerendmenu 21820793a61dSThomas Gleixner 2183091f6e26SDavid Howellsconfig SYSTEM_DATA_VERIFICATION 2184091f6e26SDavid Howells def_bool n 2185091f6e26SDavid Howells select SYSTEM_TRUSTED_KEYRING 2186091f6e26SDavid Howells select KEYS 2187091f6e26SDavid Howells select CRYPTO 2188d43de6c7SDavid Howells select CRYPTO_RSA 2189091f6e26SDavid Howells select ASYMMETRIC_KEY_TYPE 2190091f6e26SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2191091f6e26SDavid Howells select ASN1 2192091f6e26SDavid Howells select OID_REGISTRY 2193091f6e26SDavid Howells select X509_CERTIFICATE_PARSER 2194091f6e26SDavid Howells select PKCS7_MESSAGE_PARSER 219582c04ff8SPeter Foley help 2196091f6e26SDavid Howells Provide PKCS#7 message verification using the contents of the system 2197091f6e26SDavid Howells trusted keyring to provide public keys. This then can be used for 2198091f6e26SDavid Howells module verification, kexec image verification and firmware blob 2199091f6e26SDavid Howells verification. 220082c04ff8SPeter Foley 2201125e5645SMathieu Desnoyersconfig PROFILING 2202b309a294SRobert Richter bool "Profiling support" 2203125e5645SMathieu Desnoyers help 2204125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 2205f8408264SViresh Kumar by profilers. 2206125e5645SMathieu Desnoyers 22072f7ab126SMiguel Ojedaconfig RUST 22082f7ab126SMiguel Ojeda bool "Rust support" 22092f7ab126SMiguel Ojeda depends on HAVE_RUST 22102f7ab126SMiguel Ojeda depends on RUST_IS_AVAILABLE 2211ac61506bSSami Tolvanen select EXTENDED_MODVERSIONS if MODVERSIONS 2212ac61506bSSami Tolvanen depends on !MODVERSIONS || GENDWARFKSYMS 2213f1385dc6SNeal Gompa depends on !GCC_PLUGIN_RANDSTRUCT 22142f7ab126SMiguel Ojeda depends on !RANDSTRUCT 22155daa0c35SMatthew Maurer depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 221623ef9d43SKees Cook depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 221723ef9d43SKees Cook select CFI_ICALL_NORMALIZE_INTEGERS if CFI 22185b271543SAlice Ryhl depends on !KASAN || CC_IS_CLANG 221972d33b8bSAlice Ryhl depends on !KASAN_SW_TAGS || RUSTC_VERSION >= 109600 22202f7ab126SMiguel Ojeda help 22212f7ab126SMiguel Ojeda Enables Rust support in the kernel. 22222f7ab126SMiguel Ojeda 22232f7ab126SMiguel Ojeda This allows other Rust-related options, like drivers written in Rust, 22242f7ab126SMiguel Ojeda to be selected. 22252f7ab126SMiguel Ojeda 22262f7ab126SMiguel Ojeda It is also required to be able to load external kernel modules 22272f7ab126SMiguel Ojeda written in Rust. 22282f7ab126SMiguel Ojeda 22292f7ab126SMiguel Ojeda See Documentation/rust/ for more information. 22302f7ab126SMiguel Ojeda 22312f7ab126SMiguel Ojeda If unsure, say N. 22322f7ab126SMiguel Ojeda 2233*e74b7a3fSYury Norovsource "rust/kernel/Kconfig.test" 2234*e74b7a3fSYury Norov 22352f7ab126SMiguel Ojedaconfig RUSTC_VERSION_TEXT 22362f7ab126SMiguel Ojeda string 22372f7ab126SMiguel Ojeda depends on RUST 22385134a335SMiguel Ojeda default "$(RUSTC_VERSION_TEXT)" 22395134a335SMiguel Ojeda help 22405134a335SMiguel Ojeda See `CC_VERSION_TEXT`. 22412f7ab126SMiguel Ojeda 22422f7ab126SMiguel Ojedaconfig BINDGEN_VERSION_TEXT 22432f7ab126SMiguel Ojeda string 22442f7ab126SMiguel Ojeda depends on RUST 224593553d99SMiguel Ojeda default "$(shell,$(BINDGEN) --version 2>/dev/null)" 22462f7ab126SMiguel Ojeda 22475f87f112SIngo Molnar# 22485f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 22495f87f112SIngo Molnar# dynamically changed for a probe function. 22505f87f112SIngo Molnar# 225197e1c18eSMathieu Desnoyersconfig TRACEPOINTS 22525f87f112SIngo Molnar bool 2253a363d27cSMathieu Desnoyers select TASKS_TRACE_RCU 225497e1c18eSMathieu Desnoyers 225589cde455SEric DeVoldersource "kernel/Kconfig.kexec" 225689cde455SEric DeVolder 225748a1b232SPasha Tatashinsource "kernel/liveupdate/Kconfig" 225848a1b232SPasha Tatashin 22591da177e4SLinus Torvaldsendmenu # General setup 22601da177e4SLinus Torvalds 22611572497cSChristoph Hellwigsource "arch/Kconfig" 22621572497cSChristoph Hellwig 2263ae81f9e3SChuck Ebbertconfig RT_MUTEXES 22646341e62bSChristoph Jaeger bool 22651c6f9ec0SSebastian Andrzej Siewior default y if PREEMPT_RT 2266ae81f9e3SChuck Ebbert 2267c8424e77SThiago Jung Bauermannconfig MODULE_SIG_FORMAT 2268c8424e77SThiago Jung Bauermann def_bool n 2269c8424e77SThiago Jung Bauermann select SYSTEM_DATA_VERIFICATION 2270c8424e77SThiago Jung Bauermann 227173b4fc92SChristophe Leroysource "kernel/module/Kconfig" 22726c9692e2SPeter Zijlstra 227398a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 227498a79d6aSRusty Russell bool 227598a79d6aSRusty Russell help 22765f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 22775f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 227898a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 227998a79d6aSRusty Russell it was better to provide this option than to break all the archs 2280692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 228198a79d6aSRusty Russell 22823a65dfe8SJens Axboesource "block/Kconfig" 2283e98c3202SAvi Kivity 2284e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 2285e98c3202SAvi Kivity bool 2286e260be67SPaul E. McKenney 228716295becSSteffen Klassertconfig PADATA 228816295becSSteffen Klassert depends on SMP 228916295becSSteffen Klassert bool 229016295becSSteffen Klassert 22914520c6a4SDavid Howellsconfig ASN1 22924520c6a4SDavid Howells tristate 22934520c6a4SDavid Howells help 22944520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 22954520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 22964520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 22974520c6a4SDavid Howells functions to call on what tags. 22984520c6a4SDavid Howells 22996beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 2300e61938a9SMathieu Desnoyers 23010ebeea8cSDaniel Borkmannconfig ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 23020ebeea8cSDaniel Borkmann bool 23030ebeea8cSDaniel Borkmann 23044ff4c745SAndrea Parriconfig ARCH_HAS_PREPARE_SYNC_CORE_CMD 23054ff4c745SAndrea Parri bool 23064ff4c745SAndrea Parri 2307e61938a9SMathieu Desnoyersconfig ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2308e61938a9SMathieu Desnoyers bool 23091bd21c6cSDominik Brodowski 23101bd21c6cSDominik Brodowski# It may be useful for an architecture to override the definitions of the 23117303e30eSDominik Brodowski# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 23127303e30eSDominik Brodowski# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 23137303e30eSDominik Brodowski# different calling convention for syscalls. They can also override the 23147303e30eSDominik Brodowski# macros for not-implemented syscalls in kernel/sys_ni.c and 23157303e30eSDominik Brodowski# kernel/time/posix-stubs.c. All these overrides need to be available in 23167303e30eSDominik Brodowski# <asm/syscall_wrapper.h>. 23171bd21c6cSDominik Brodowskiconfig ARCH_HAS_SYSCALL_WRAPPER 23181bd21c6cSDominik Brodowski def_bool n 2319