1ec8f24b7SThomas Gleixner# SPDX-License-Identifier: GPL-2.0-only 28b59cd81SMasahiro Yamadaconfig CC_VERSION_TEXT 38b59cd81SMasahiro Yamada string 48b59cd81SMasahiro Yamada default "$(CC_VERSION_TEXT)" 58b59cd81SMasahiro Yamada help 68b59cd81SMasahiro Yamada This is used in unclear ways: 78b59cd81SMasahiro Yamada 88b59cd81SMasahiro Yamada - Re-run Kconfig when the compiler is updated 98b59cd81SMasahiro Yamada The 'default' property references the environment variable, 108b59cd81SMasahiro Yamada CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd. 118b59cd81SMasahiro Yamada When the compiler is updated, Kconfig will be invoked. 128b59cd81SMasahiro Yamada 13f9c8bc46SBhaskar Chowdhury - Ensure full rebuild when the compiler is updated 14ce6ed1c4SMasahiro Yamada include/linux/compiler-version.h contains this option in the comment 150e0345b7SAlexey Dobriyan line so fixdep adds include/config/CC_VERSION_TEXT into the 16ce6ed1c4SMasahiro Yamada auto-generated dependency. When the compiler is updated, syncconfig 17ce6ed1c4SMasahiro Yamada will touch it and then every file will be rebuilt. 188b59cd81SMasahiro Yamada 19a4353898SMasahiro Yamadaconfig CC_IS_GCC 20aec6c60aSMasahiro Yamada def_bool $(success,test "$(cc-name)" = GCC) 21a4353898SMasahiro Yamada 22a4353898SMasahiro Yamadaconfig GCC_VERSION 23a4353898SMasahiro Yamada int 24aec6c60aSMasahiro Yamada default $(cc-version) if CC_IS_GCC 25a4353898SMasahiro Yamada default 0 26a4353898SMasahiro Yamada 27469cb737SMasahiro Yamadaconfig CC_IS_CLANG 28aec6c60aSMasahiro Yamada def_bool $(success,test "$(cc-name)" = Clang) 29b744b43fSSami Tolvanen 30469cb737SMasahiro Yamadaconfig CLANG_VERSION 31469cb737SMasahiro Yamada int 32aec6c60aSMasahiro Yamada default $(cc-version) if CC_IS_CLANG 33aec6c60aSMasahiro Yamada default 0 34469cb737SMasahiro Yamada 35ba64beb1SMasahiro Yamadaconfig AS_IS_GNU 36ba64beb1SMasahiro Yamada def_bool $(success,test "$(as-name)" = GNU) 37ba64beb1SMasahiro Yamada 38ba64beb1SMasahiro Yamadaconfig AS_IS_LLVM 39ba64beb1SMasahiro Yamada def_bool $(success,test "$(as-name)" = LLVM) 40ba64beb1SMasahiro Yamada 41ba64beb1SMasahiro Yamadaconfig AS_VERSION 42ba64beb1SMasahiro Yamada int 43ba64beb1SMasahiro Yamada # Use clang version if this is the integrated assembler 44ba64beb1SMasahiro Yamada default CLANG_VERSION if AS_IS_LLVM 45ba64beb1SMasahiro Yamada default $(as-version) 46ba64beb1SMasahiro Yamada 4702aff859SMasahiro Yamadaconfig LD_IS_BFD 4802aff859SMasahiro Yamada def_bool $(success,test "$(ld-name)" = BFD) 4902aff859SMasahiro Yamada 5002aff859SMasahiro Yamadaconfig LD_VERSION 5102aff859SMasahiro Yamada int 5202aff859SMasahiro Yamada default $(ld-version) if LD_IS_BFD 5302aff859SMasahiro Yamada default 0 5402aff859SMasahiro Yamada 5502aff859SMasahiro Yamadaconfig LD_IS_LLD 5602aff859SMasahiro Yamada def_bool $(success,test "$(ld-name)" = LLD) 57c65eacbeSAndy Lutomirski 58d5750cd3SNathan Chancellorconfig LLD_VERSION 59d5750cd3SNathan Chancellor int 6002aff859SMasahiro Yamada default $(ld-version) if LD_IS_LLD 6102aff859SMasahiro Yamada default 0 62d5750cd3SNathan Chancellor 636e74c6b5SMiguel Ojedaconfig RUSTC_VERSION 646e74c6b5SMiguel Ojeda int 65af0121c2SGary Guo default $(rustc-version) 666e74c6b5SMiguel Ojeda help 676e74c6b5SMiguel Ojeda It does not depend on `RUST` since that one may need to use the version 686e74c6b5SMiguel Ojeda in a `depends on`. 696e74c6b5SMiguel Ojeda 702f7ab126SMiguel Ojedaconfig RUST_IS_AVAILABLE 712f7ab126SMiguel Ojeda def_bool $(success,$(srctree)/scripts/rust_is_available.sh) 722f7ab126SMiguel Ojeda help 732f7ab126SMiguel Ojeda This shows whether a suitable Rust toolchain is available (found). 742f7ab126SMiguel Ojeda 752f7ab126SMiguel Ojeda Please see Documentation/rust/quick-start.rst for instructions on how 76eacf96d2SColin Ian King to satisfy the build requirements of Rust support. 772f7ab126SMiguel Ojeda 782f7ab126SMiguel Ojeda In particular, the Makefile target 'rustavailable' is useful to check 792f7ab126SMiguel Ojeda why the Rust toolchain is not being detected. 802f7ab126SMiguel Ojeda 81af0121c2SGary Guoconfig RUSTC_LLVM_VERSION 82af0121c2SGary Guo int 83af0121c2SGary Guo default $(rustc-llvm-version) 84af0121c2SGary Guo 85deab487eSThomas Weißschuhconfig ARCH_HAS_CC_CAN_LINK 86deab487eSThomas Weißschuh bool 87deab487eSThomas Weißschuh 881a927fd3SMasahiro Yamadaconfig CC_CAN_LINK 899371f86eSMasahiro Yamada bool 90deab487eSThomas Weißschuh default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK 9180623f2cSThomas Weißschuh default $(cc_can_link_user,$(m64-flag)) if 64BIT 9280623f2cSThomas Weißschuh default $(cc_can_link_user,$(m32-flag)) 931a927fd3SMasahiro Yamada 94f2f6a8e8SMark Rutland# Fixed in GCC 14, 13.3, 12.4 and 11.5 95f2f6a8e8SMark Rutland# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 96f2f6a8e8SMark Rutlandconfig GCC_ASM_GOTO_OUTPUT_BROKEN 97f2f6a8e8SMark Rutland bool 98f2f6a8e8SMark Rutland depends on CC_IS_GCC 99f2f6a8e8SMark Rutland default y if GCC_VERSION < 110500 100f2f6a8e8SMark Rutland default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 101f2f6a8e8SMark Rutland default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 102f2f6a8e8SMark Rutland 103587f1701SNick Desaulniersconfig CC_HAS_ASM_GOTO_OUTPUT 104f2f6a8e8SMark Rutland def_bool y 105f2f6a8e8SMark Rutland depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 106e2ffa15bSThomas Gleixner # Detect basic support 107f2f6a8e8SMark Rutland depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) 108e2ffa15bSThomas Gleixner # Detect clang (< v17) scoped label issues 109fde0ab43SLinus Torvalds depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) 110587f1701SNick Desaulniers 1111aa0e8b1SSean Christophersonconfig CC_HAS_ASM_GOTO_TIED_OUTPUT 1121aa0e8b1SSean Christopherson depends on CC_HAS_ASM_GOTO_OUTPUT 1131aa0e8b1SSean Christopherson # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 114534bd703SAlexandre Belloni def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null) 1151aa0e8b1SSean Christopherson 1165cf896fbSPeter Collingbourneconfig TOOLS_SUPPORT_RELR 1172d122942SWill Deacon def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 1185cf896fbSPeter Collingbourne 119eb111869SRasmus Villemoesconfig CC_HAS_ASM_INLINE 120eb111869SRasmus Villemoes def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 121eb111869SRasmus Villemoes 122f72e2cffSHeiko Carstensconfig CC_HAS_ASSUME 123f72e2cffSHeiko Carstens bool 124f72e2cffSHeiko Carstens # clang needs to be at least 19.1.0 since the meaning of the assume 125f72e2cffSHeiko Carstens # attribute changed: 126f72e2cffSHeiko Carstens # https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17 127f72e2cffSHeiko Carstens default y if CC_IS_CLANG && CLANG_VERSION >= 190100 128f72e2cffSHeiko Carstens # supported since gcc 13.1.0 129f72e2cffSHeiko Carstens # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654 130f72e2cffSHeiko Carstens default y if CC_IS_GCC && GCC_VERSION >= 130100 131f72e2cffSHeiko Carstens 13251c2ee6dSNick Desaulniersconfig CC_HAS_NO_PROFILE_FN_ATTR 13351c2ee6dSNick Desaulniers def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 13451c2ee6dSNick Desaulniers 135f06e108aSJan Hendrik Farrconfig CC_HAS_COUNTED_BY 1365106c650SJan Hendrik Farr bool 13786a9b125SNathan Chancellor # clang needs to be at least 20.1.0 to avoid potential crashes 13886a9b125SNathan Chancellor # when building structures that contain __counted_by 13986a9b125SNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/2114 14086a9b125SNathan Chancellor # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 14186a9b125SNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION >= 200100 1425106c650SJan Hendrik Farr # supported since gcc 15.1.0 1435106c650SJan Hendrik Farr # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 1445106c650SJan Hendrik Farr default y if CC_IS_GCC && GCC_VERSION >= 150100 145f06e108aSJan Hendrik Farr 146150a04d8SBill Wendlingconfig CC_HAS_COUNTED_BY_PTR 147150a04d8SBill Wendling bool 148150a04d8SBill Wendling # supported since clang 22 149150a04d8SBill Wendling default y if CC_IS_CLANG && CLANG_VERSION >= 220000 150150a04d8SBill Wendling # supported since gcc 16.0.0 151150a04d8SBill Wendling default y if CC_IS_GCC && GCC_VERSION >= 160000 152150a04d8SBill Wendling 153d39a1d74SKees Cookconfig CC_HAS_BROKEN_COUNTED_BY_REF 154d39a1d74SKees Cook bool 155d39a1d74SKees Cook # https://github.com/llvm/llvm-project/issues/182575 156f709859fSNathan Chancellor default y if CC_IS_CLANG && CLANG_VERSION < 220100 157d39a1d74SKees Cook 158b688f369SKees Cookconfig CC_HAS_MULTIDIMENSIONAL_NONSTRING 159b688f369SKees Cook def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 160b688f369SKees Cook 161e7607f7dSNathan Chancellorconfig LD_CAN_USE_KEEP_IN_OVERLAY 162e7607f7dSNathan Chancellor # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 163e7607f7dSNathan Chancellor # https://github.com/llvm/llvm-project/pull/130661 164e7607f7dSNathan Chancellor def_bool LD_IS_BFD || LLD_VERSION >= 210000 165e7607f7dSNathan Chancellor 16688622323SAlexandre Courbotconfig RUSTC_HAS_SLICE_AS_FLATTENED 16788622323SAlexandre Courbot def_bool RUSTC_VERSION >= 108000 16888622323SAlexandre Courbot 16947cb6bf7SXiangfei Dingconfig RUSTC_HAS_COERCE_POINTEE 17047cb6bf7SXiangfei Ding def_bool RUSTC_VERSION >= 108400 17147cb6bf7SXiangfei Ding 17236174d16SMiguel Ojedaconfig RUSTC_HAS_SPAN_FILE 17336174d16SMiguel Ojeda def_bool RUSTC_VERSION >= 108800 17436174d16SMiguel Ojeda 1757129ea6eSMiguel Ojedaconfig RUSTC_HAS_UNNECESSARY_TRANSMUTES 1767129ea6eSMiguel Ojeda def_bool RUSTC_VERSION >= 108800 1777129ea6eSMiguel Ojeda 1780aa2b78cSBoqun Fengconfig RUSTC_HAS_FILE_WITH_NUL 1790aa2b78cSBoqun Feng def_bool RUSTC_VERSION >= 108900 1800aa2b78cSBoqun Feng 181c09461a0SAlice Ryhlconfig RUSTC_HAS_FILE_AS_C_STR 182c09461a0SAlice Ryhl def_bool RUSTC_VERSION >= 109100 183c09461a0SAlice Ryhl 184613fe169SNathan Chancellorconfig PAHOLE_VERSION 185613fe169SNathan Chancellor int 18690e5b38aSIhor Solodrai default "$(PAHOLE_VERSION)" 187613fe169SNathan Chancellor 188b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS 189b99b87f7SPeter Oberparleiter bool 190b99b87f7SPeter Oberparleiter 191e360adbeSPeter Zijlstraconfig IRQ_WORK 192fd0a68a2STejun Heo def_bool y if SMP 193e360adbeSPeter Zijlstra 19410916706SShile Zhangconfig BUILDTIME_TABLE_SORT 1951dbdc6f1SDavid Daney bool 1961dbdc6f1SDavid Daney 197c65eacbeSAndy Lutomirskiconfig THREAD_INFO_IN_TASK 198c65eacbeSAndy Lutomirski bool 199c65eacbeSAndy Lutomirski help 200c65eacbeSAndy Lutomirski Select this to move thread_info off the stack into task_struct. To 201c65eacbeSAndy Lutomirski make this work, an arch will need to remove all thread_info fields 202c65eacbeSAndy Lutomirski except flags and fix any runtime bugs. 203c65eacbeSAndy Lutomirski 204c6c314a6SAndy Lutomirski One subtle change that will be needed is to use try_get_task_stack() 205c6c314a6SAndy Lutomirski and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 206c6c314a6SAndy Lutomirski 207ff0cfc66SAl Boldimenu "General setup" 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvaldsconfig BROKEN 2101da177e4SLinus Torvalds bool 211fefbeed8SAndrew Morton help 212fefbeed8SAndrew Morton This option allows you to choose whether you want to try to 213fefbeed8SAndrew Morton compile (and fix) old drivers that haven't been updated to 214fefbeed8SAndrew Morton new infrastructure. 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 2171da177e4SLinus Torvalds bool 2181da177e4SLinus Torvalds depends on BROKEN || !SMP 2191da177e4SLinus Torvalds default y 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 2221da177e4SLinus Torvalds int 223dd673bcaSAdrian Bunk default 32 if !UML 224dd673bcaSAdrian Bunk default 128 if UML 2251da177e4SLinus Torvalds help 22634ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 22734ad92c2SRandy Dunlap variables passed to init from the kernel command line. 2281da177e4SLinus Torvalds 2294bb16672SJiri Slabyconfig COMPILE_TEST 2304bb16672SJiri Slaby bool "Compile also drivers which will not load" 231ea29b20aSMasahiro Yamada depends on HAS_IOMEM 2324bb16672SJiri Slaby help 2334bb16672SJiri Slaby Some drivers can be compiled on a different platform than they are 2344bb16672SJiri Slaby intended to be run on. Despite they cannot be loaded there (or even 2354bb16672SJiri Slaby when they load they cannot be used due to missing HW support), 2364bb16672SJiri Slaby developers still, opposing to distributors, might want to build such 2374bb16672SJiri Slaby drivers to compile-test them. 2384bb16672SJiri Slaby 2394bb16672SJiri Slaby If you are a developer and want to build everything available, say Y 2404bb16672SJiri Slaby here. If you are a user/distributor, say N here to exclude useless 2414bb16672SJiri Slaby drivers to be distributed. 2424bb16672SJiri Slaby 2433fe617ccSLinus Torvaldsconfig WERROR 2443fe617ccSLinus Torvalds bool "Compile the kernel with warnings as errors" 245b339ec9cSMarco Elver default COMPILE_TEST 2463fe617ccSLinus Torvalds help 2473fe617ccSLinus Torvalds A kernel build should not cause any compiler warnings, and this 2482f7ab126SMiguel Ojeda enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 249e1789d7cSXin Li to enforce that rule by default. Certain warnings from other tools 250e1789d7cSXin Li such as the linker may be upgraded to errors with this option as 251e1789d7cSXin Li well. 2523fe617ccSLinus Torvalds 253e1789d7cSXin Li However, if you have a new (or very old) compiler or linker with odd 254e1789d7cSXin Li and unusual warnings, or you have some architecture with problems, 2553fe617ccSLinus Torvalds you may need to disable this config option in order to 2563fe617ccSLinus Torvalds successfully build the kernel. 2573fe617ccSLinus Torvalds 2583fe617ccSLinus Torvalds If in doubt, say Y. 2593fe617ccSLinus Torvalds 260d6fc9fcbSMasahiro Yamadaconfig UAPI_HEADER_TEST 261d6fc9fcbSMasahiro Yamada bool "Compile test UAPI headers" 2622a0a3080SThomas Weißschuh depends on HEADERS_INSTALL 263d6fc9fcbSMasahiro Yamada help 264d6fc9fcbSMasahiro Yamada Compile test headers exported to user-space to ensure they are 265d6fc9fcbSMasahiro Yamada self-contained, i.e. compilable as standalone units. 266d6fc9fcbSMasahiro Yamada 267d6fc9fcbSMasahiro Yamada If you are a developer or tester and want to ensure the exported 268d6fc9fcbSMasahiro Yamada headers are self-contained, say Y here. Otherwise, choose N. 269d6fc9fcbSMasahiro Yamada 2701da177e4SLinus Torvaldsconfig LOCALVERSION 2711da177e4SLinus Torvalds string "Local version - append to kernel release" 2721da177e4SLinus Torvalds help 2731da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 2741da177e4SLinus Torvalds This will show up when you type uname, for example. 2751da177e4SLinus Torvalds The string you set here will be appended after the contents of 2761da177e4SLinus Torvalds any files with a filename matching localversion* in your 2771da177e4SLinus Torvalds object and source tree, in that order. Your total string can 2781da177e4SLinus Torvalds be a maximum of 64 characters. 2791da177e4SLinus Torvalds 280aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 281aaebf433SRyan Anderson bool "Automatically append version information to the version string" 282aaebf433SRyan Anderson default y 283ac3339baSAlexey Dobriyan depends on !COMPILE_TEST 284aaebf433SRyan Anderson help 285aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 2866e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 2876e5a5420SRobert P. J. Day top of tree revision. 288aaebf433SRyan Anderson 289aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 2906e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 291aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 2926e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 293aaebf433SRyan Anderson 2940f9c608dSRasmus Villemoes (The actual string used here is the first 12 characters produced 2956e5a5420SRobert P. J. Day by running the command: 2966e5a5420SRobert P. J. Day 2976e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 2986e5a5420SRobert P. J. Day 2996e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 300aaebf433SRyan Anderson 3019afb719eSLaura Abbottconfig BUILD_SALT 3029afb719eSLaura Abbott string "Build ID Salt" 3039afb719eSLaura Abbott default "" 3049afb719eSLaura Abbott help 3059afb719eSLaura Abbott The build ID is used to link binaries and their debug info. Setting 3069afb719eSLaura Abbott this option will use the value in the calculation of the build id. 3079afb719eSLaura Abbott This is mostly useful for distributions which want to ensure the 3089afb719eSLaura Abbott build is unique between builds. It's safe to leave the default. 3099afb719eSLaura Abbott 3102e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP 3112e9f3bddSH. Peter Anvin bool 3122e9f3bddSH. Peter Anvin 3132e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2 3142e9f3bddSH. Peter Anvin bool 3152e9f3bddSH. Peter Anvin 3162e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA 3172e9f3bddSH. Peter Anvin bool 3182e9f3bddSH. Peter Anvin 3193ebe1243SLasse Collinconfig HAVE_KERNEL_XZ 3203ebe1243SLasse Collin bool 3213ebe1243SLasse Collin 3227dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO 3237dd65febSAlbin Tonnerre bool 3247dd65febSAlbin Tonnerre 325e76e1fdfSKyungsik Leeconfig HAVE_KERNEL_LZ4 326e76e1fdfSKyungsik Lee bool 327e76e1fdfSKyungsik Lee 32848f7ddf7SNick Terrellconfig HAVE_KERNEL_ZSTD 32948f7ddf7SNick Terrell bool 33048f7ddf7SNick Terrell 331f16466afSVasily Gorbikconfig HAVE_KERNEL_UNCOMPRESSED 332f16466afSVasily Gorbik bool 333f16466afSVasily Gorbik 33430d65dbfSAlain Knaffchoice 33530d65dbfSAlain Knaff prompt "Kernel compression mode" 33630d65dbfSAlain Knaff default KERNEL_GZIP 33748f7ddf7SNick 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 33830d65dbfSAlain Knaff help 33930d65dbfSAlain Knaff The linux kernel is a kind of self-extracting executable. 34030d65dbfSAlain Knaff Several compression algorithms are available, which differ 34130d65dbfSAlain Knaff in efficiency, compression and decompression speed. 34230d65dbfSAlain Knaff Compression speed is only relevant when building a kernel. 34330d65dbfSAlain Knaff Decompression speed is relevant at each boot. 34430d65dbfSAlain Knaff 34530d65dbfSAlain Knaff If you have any problems with bzip2 or lzma compressed 34630d65dbfSAlain Knaff kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 34730d65dbfSAlain Knaff version of this functionality (bzip2 only), for 2.4, was 34830d65dbfSAlain Knaff supplied by Christian Ludwig) 34930d65dbfSAlain Knaff 35030d65dbfSAlain Knaff High compression options are mostly useful for users, who 35130d65dbfSAlain Knaff are low on disk space (embedded systems), but for whom ram 35230d65dbfSAlain Knaff size matters less. 35330d65dbfSAlain Knaff 35430d65dbfSAlain Knaff If in doubt, select 'gzip' 35530d65dbfSAlain Knaff 35630d65dbfSAlain Knaffconfig KERNEL_GZIP 35730d65dbfSAlain Knaff bool "Gzip" 3582e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_GZIP 35930d65dbfSAlain Knaff help 3607dd65febSAlbin Tonnerre The old and tried gzip compression. It provides a good balance 3617dd65febSAlbin Tonnerre between compression ratio and decompression speed. 36230d65dbfSAlain Knaff 36330d65dbfSAlain Knaffconfig KERNEL_BZIP2 36430d65dbfSAlain Knaff bool "Bzip2" 3652e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_BZIP2 36630d65dbfSAlain Knaff help 36730d65dbfSAlain Knaff Its compression ratio and speed is intermediate. 3680a4dd35cSRandy Dunlap Decompression speed is slowest among the choices. The kernel 3692e9f3bddSH. Peter Anvin size is about 10% smaller with bzip2, in comparison to gzip. 3702e9f3bddSH. Peter Anvin Bzip2 uses a large amount of memory. For modern kernels you 3712e9f3bddSH. Peter Anvin will need at least 8MB RAM or more for booting. 37230d65dbfSAlain Knaff 37330d65dbfSAlain Knaffconfig KERNEL_LZMA 37430d65dbfSAlain Knaff bool "LZMA" 3752e9f3bddSH. Peter Anvin depends on HAVE_KERNEL_LZMA 37630d65dbfSAlain Knaff help 3770a4dd35cSRandy Dunlap This compression algorithm's ratio is best. Decompression speed 3780a4dd35cSRandy Dunlap is between gzip and bzip2. Compression is slowest. 3790a4dd35cSRandy Dunlap The kernel size is about 33% smaller with LZMA in comparison to gzip. 38030d65dbfSAlain Knaff 3813ebe1243SLasse Collinconfig KERNEL_XZ 3823ebe1243SLasse Collin bool "XZ" 3833ebe1243SLasse Collin depends on HAVE_KERNEL_XZ 3843ebe1243SLasse Collin help 3853ebe1243SLasse Collin XZ uses the LZMA2 algorithm and instruction set specific 3863ebe1243SLasse Collin BCJ filters which can improve compression ratio of executable 3873ebe1243SLasse Collin code. The size of the kernel is about 30% smaller with XZ in 3883ebe1243SLasse Collin comparison to gzip. On architectures for which there is a BCJ 3897472ff8aSLasse Collin filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 3907472ff8aSLasse Collin and SPARC), XZ will create a few percent smaller kernel than 3917472ff8aSLasse Collin plain LZMA. 3923ebe1243SLasse Collin 3933ebe1243SLasse Collin The speed is about the same as with LZMA: The decompression 3943ebe1243SLasse Collin speed of XZ is better than that of bzip2 but worse than gzip 3953ebe1243SLasse Collin and LZO. Compression is slow. 3963ebe1243SLasse Collin 3977dd65febSAlbin Tonnerreconfig KERNEL_LZO 3987dd65febSAlbin Tonnerre bool "LZO" 3997dd65febSAlbin Tonnerre depends on HAVE_KERNEL_LZO 4007dd65febSAlbin Tonnerre help 4010a4dd35cSRandy Dunlap Its compression ratio is the poorest among the choices. The kernel 402681b3049SStephan Sperber size is about 10% bigger than gzip; however its speed 4037dd65febSAlbin Tonnerre (both compression and decompression) is the fastest. 4047dd65febSAlbin Tonnerre 405e76e1fdfSKyungsik Leeconfig KERNEL_LZ4 406e76e1fdfSKyungsik Lee bool "LZ4" 407e76e1fdfSKyungsik Lee depends on HAVE_KERNEL_LZ4 408e76e1fdfSKyungsik Lee help 409e76e1fdfSKyungsik Lee LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 410e76e1fdfSKyungsik Lee A preliminary version of LZ4 de/compression tool is available at 411e76e1fdfSKyungsik Lee <https://code.google.com/p/lz4/>. 412e76e1fdfSKyungsik Lee 413e76e1fdfSKyungsik Lee Its compression ratio is worse than LZO. The size of the kernel 414e76e1fdfSKyungsik Lee is about 8% bigger than LZO. But the decompression speed is 415e76e1fdfSKyungsik Lee faster than LZO. 416e76e1fdfSKyungsik Lee 41748f7ddf7SNick Terrellconfig KERNEL_ZSTD 41848f7ddf7SNick Terrell bool "ZSTD" 41948f7ddf7SNick Terrell depends on HAVE_KERNEL_ZSTD 42048f7ddf7SNick Terrell help 42148f7ddf7SNick Terrell ZSTD is a compression algorithm targeting intermediate compression 42248f7ddf7SNick Terrell with fast decompression speed. It will compress better than GZIP and 42348f7ddf7SNick Terrell decompress around the same speed as LZO, but slower than LZ4. You 42448f7ddf7SNick Terrell will need at least 192 KB RAM or more for booting. The zstd command 42548f7ddf7SNick Terrell line tool is required for compression. 42648f7ddf7SNick Terrell 427f16466afSVasily Gorbikconfig KERNEL_UNCOMPRESSED 428f16466afSVasily Gorbik bool "None" 429f16466afSVasily Gorbik depends on HAVE_KERNEL_UNCOMPRESSED 430f16466afSVasily Gorbik help 431f16466afSVasily Gorbik Produce uncompressed kernel image. This option is usually not what 432f16466afSVasily Gorbik you want. It is useful for debugging the kernel in slow simulation 433f16466afSVasily Gorbik environments, where decompressing and moving the kernel is awfully 434f16466afSVasily Gorbik slow. This option allows early boot code to skip the decompressor 435f16466afSVasily Gorbik and jump right at uncompressed kernel image. 436f16466afSVasily Gorbik 43730d65dbfSAlain Knaffendchoice 43830d65dbfSAlain Knaff 439ada4ab7aSChris Downconfig DEFAULT_INIT 440ada4ab7aSChris Down string "Default init path" 441ada4ab7aSChris Down default "" 442ada4ab7aSChris Down help 443ada4ab7aSChris Down This option determines the default init for the system if no init= 444ada4ab7aSChris Down option is passed on the kernel command line. If the requested path is 445ada4ab7aSChris Down not present, we will still then move on to attempting further 446ada4ab7aSChris Down locations (e.g. /sbin/init, etc). If this is empty, we will just use 447ada4ab7aSChris Down the fallback list when init= is not passed. 448ada4ab7aSChris Down 449bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME 450bd5dc17bSJosh Triplett string "Default hostname" 451bd5dc17bSJosh Triplett default "(none)" 452bd5dc17bSJosh Triplett help 453bd5dc17bSJosh Triplett This option determines the default system hostname before userspace 454bd5dc17bSJosh Triplett calls sethostname(2). The kernel traditionally uses "(none)" here, 455bd5dc17bSJosh Triplett but you may wish to use a different default here to make a minimal 456bd5dc17bSJosh Triplett system more usable with less configuration. 457bd5dc17bSJosh Triplett 4581da177e4SLinus Torvaldsconfig SYSVIPC 4591da177e4SLinus Torvalds bool "System V IPC" 460a7f7f624SMasahiro Yamada help 4611da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 4621da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 4631da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 4641da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 4651da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 4661da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 4671da177e4SLinus Torvalds you'll need to say Y here. 4681da177e4SLinus Torvalds 4691da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 4701da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 4711da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 4721da177e4SLinus Torvalds 473a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 474a5494dcdSEric W. Biederman bool 475a5494dcdSEric W. Biederman depends on SYSVIPC 476a5494dcdSEric W. Biederman depends on SYSCTL 477a5494dcdSEric W. Biederman default y 478a5494dcdSEric W. Biederman 4790cbed0eeSGuo Renconfig SYSVIPC_COMPAT 4800cbed0eeSGuo Ren def_bool y 4810cbed0eeSGuo Ren depends on COMPAT && SYSVIPC 4820cbed0eeSGuo Ren 4831da177e4SLinus Torvaldsconfig POSIX_MQUEUE 4841da177e4SLinus Torvalds bool "POSIX Message Queues" 48519c92399SKees Cook depends on NET 486a7f7f624SMasahiro Yamada help 4871da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 4881da177e4SLinus Torvalds queues every message has a priority which decides about succession 4891da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 4901da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 491b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 4921da177e4SLinus Torvalds 4931da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 4941da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 4951da177e4SLinus Torvalds operations on message queues. 4961da177e4SLinus Torvalds 4971da177e4SLinus Torvalds If unsure, say Y. 4981da177e4SLinus Torvalds 499bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL 500bdc8e5f8SSerge E. Hallyn bool 501bdc8e5f8SSerge E. Hallyn depends on POSIX_MQUEUE 502bdc8e5f8SSerge E. Hallyn depends on SYSCTL 503bdc8e5f8SSerge E. Hallyn default y 504bdc8e5f8SSerge E. Hallyn 505c73be61cSDavid Howellsconfig WATCH_QUEUE 506c73be61cSDavid Howells bool "General notification queue" 507c73be61cSDavid Howells default n 508c73be61cSDavid Howells help 509c73be61cSDavid Howells 510c73be61cSDavid Howells This is a general notification queue for the kernel to pass events to 511c73be61cSDavid Howells userspace by splicing them into pipes. It can be used in conjunction 512c73be61cSDavid Howells with watches for key/keyring change notifications and device 513c73be61cSDavid Howells notifications. 514c73be61cSDavid Howells 515c02b872aSMauro Carvalho Chehab See Documentation/core-api/watch_queue.rst 516c73be61cSDavid Howells 517226b4ccdSKonstantin Khlebnikovconfig CROSS_MEMORY_ATTACH 518226b4ccdSKonstantin Khlebnikov bool "Enable process_vm_readv/writev syscalls" 519226b4ccdSKonstantin Khlebnikov depends on MMU 520226b4ccdSKonstantin Khlebnikov default y 521226b4ccdSKonstantin Khlebnikov help 522226b4ccdSKonstantin Khlebnikov Enabling this option adds the system calls process_vm_readv and 523226b4ccdSKonstantin Khlebnikov process_vm_writev which allow a process with the correct privileges 524a2a368d9SGeert Uytterhoeven to directly read from or write to another process' address space. 525226b4ccdSKonstantin Khlebnikov See the man page for more details. 526226b4ccdSKonstantin Khlebnikov 5271da177e4SLinus Torvaldsconfig AUDIT 5281da177e4SLinus Torvalds bool "Auditing support" 529804a6a49SChris Wright depends on NET 5301da177e4SLinus Torvalds help 5311da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 5321da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 533cb74ed27SPaul Moore logging of avc messages output). System call auditing is included 534cb74ed27SPaul Moore on architectures which support it. 5351da177e4SLinus Torvalds 5367a017721SAKASHI Takahiroconfig HAVE_ARCH_AUDITSYSCALL 5377a017721SAKASHI Takahiro bool 5387a017721SAKASHI Takahiro 5391da177e4SLinus Torvaldsconfig AUDITSYSCALL 540cb74ed27SPaul Moore def_bool y 5417a017721SAKASHI Takahiro depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 54228a3a7ebSEric Paris select FSNOTIFY 54374c3cbe3SAl Viro 544d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig" 545764e0da1SThomas Gleixnersource "kernel/time/Kconfig" 546b24abcffSDaniel Borkmannsource "kernel/bpf/Kconfig" 54787a4c375SChristoph Hellwigsource "kernel/Kconfig.preempt" 548d9817ebeSThomas Gleixner 549391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting" 550391dc69cSFrederic Weisbecker 551abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING 552abf917cdSFrederic Weisbecker bool 553abf917cdSFrederic Weisbecker 554fdf9c356SFrederic Weisbeckerchoice 555fdf9c356SFrederic Weisbecker prompt "Cputime accounting" 55602382affSNicholas Piggin default TICK_CPU_ACCOUNTING 557fdf9c356SFrederic Weisbecker 558fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting 559fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING 560fdf9c356SFrederic Weisbecker bool "Simple tick based cputime accounting" 561c58b0df1SFrederic Weisbecker depends on !S390 && !NO_HZ_FULL 562fdf9c356SFrederic Weisbecker help 563fdf9c356SFrederic Weisbecker This is the basic tick based cputime accounting that maintains 564fdf9c356SFrederic Weisbecker statistics about user, system and idle time spent on per jiffies 565fdf9c356SFrederic Weisbecker granularity. 566fdf9c356SFrederic Weisbecker 567fdf9c356SFrederic Weisbecker If unsure, say Y. 568fdf9c356SFrederic Weisbecker 569abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE 570391dc69cSFrederic Weisbecker bool "Deterministic task and CPU time accounting" 571c58b0df1SFrederic Weisbecker depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 572abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 573391dc69cSFrederic Weisbecker help 574391dc69cSFrederic Weisbecker Select this option to enable more accurate task and CPU time 575391dc69cSFrederic Weisbecker accounting. This is done by reading a CPU counter on each 576391dc69cSFrederic Weisbecker kernel entry and exit and on transitions within the kernel 577391dc69cSFrederic Weisbecker between system, softirq and hardirq state, so there is a 578391dc69cSFrederic Weisbecker small performance impact. In the case of s390 or IBM POWER > 5, 579391dc69cSFrederic Weisbecker this also enables accounting of stolen time on logically-partitioned 580391dc69cSFrederic Weisbecker systems. 581391dc69cSFrederic Weisbecker 582abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN 583abf917cdSFrederic Weisbecker bool "Full dynticks CPU time accounting" 58424a9c541SFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING_USER 585554b0004SKevin Hilman depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 586041a1574SArnd Bergmann depends on GENERIC_CLOCKEVENTS 587abf917cdSFrederic Weisbecker select VIRT_CPU_ACCOUNTING 58824a9c541SFrederic Weisbecker select CONTEXT_TRACKING_USER 589abf917cdSFrederic Weisbecker help 590abf917cdSFrederic Weisbecker Select this option to enable task and CPU time accounting on full 591abf917cdSFrederic Weisbecker dynticks systems. This accounting is implemented by watching every 592abf917cdSFrederic Weisbecker kernel-user boundaries using the context tracking subsystem. 593abf917cdSFrederic Weisbecker The accounting is thus performed at the expense of some significant 594abf917cdSFrederic Weisbecker overhead. 595abf917cdSFrederic Weisbecker 596abf917cdSFrederic Weisbecker For now this is only useful if you are working on the full 597abf917cdSFrederic Weisbecker dynticks subsystem development. 598abf917cdSFrederic Weisbecker 599abf917cdSFrederic Weisbecker If unsure, say N. 600abf917cdSFrederic Weisbecker 601b58c3584SRik van Rielendchoice 602b58c3584SRik van Riel 603fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING 604fdf9c356SFrederic Weisbecker bool "Fine granularity task level IRQ time accounting" 605b58c3584SRik van Riel depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 606fdf9c356SFrederic Weisbecker help 607fdf9c356SFrederic Weisbecker Select this option to enable fine granularity task irq time 608fdf9c356SFrederic Weisbecker accounting. This is done by reading a timestamp on each 609fdf9c356SFrederic Weisbecker transitions between softirq and hardirq state, so there can be a 610fdf9c356SFrederic Weisbecker small performance impact. 611fdf9c356SFrederic Weisbecker 612fdf9c356SFrederic Weisbecker If in doubt, say N here. 613fdf9c356SFrederic Weisbecker 61411d4afd4SVincent Guittotconfig HAVE_SCHED_AVG_IRQ 61511d4afd4SVincent Guittot def_bool y 61611d4afd4SVincent Guittot depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 61711d4afd4SVincent Guittot depends on SMP 61811d4afd4SVincent Guittot 619d4dbc991SVincent Guittotconfig SCHED_HW_PRESSURE 62098eb401dSValentin Schneider bool 621fcd7c9c3SValentin Schneider default y if ARM && ARM_CPU_TOPOLOGY 622fcd7c9c3SValentin Schneider default y if ARM64 62376504793SThara Gopinath depends on SMP 62498eb401dSValentin Schneider depends on CPU_FREQ_THERMAL 62598eb401dSValentin Schneider help 626d4dbc991SVincent Guittot Select this option to enable HW pressure accounting in the 627d4dbc991SVincent Guittot scheduler. HW pressure is the value conveyed to the scheduler 62898eb401dSValentin Schneider that reflects the reduction in CPU compute capacity resulted from 629d4dbc991SVincent Guittot HW throttling. HW throttling occurs when the performance of 630d4dbc991SVincent Guittot a CPU is capped due to high operating temperatures as an example. 63198eb401dSValentin Schneider 63298eb401dSValentin Schneider If selected, the scheduler will be able to balance tasks accordingly, 63398eb401dSValentin Schneider i.e. put less load on throttled CPUs than on non/less throttled ones. 63498eb401dSValentin Schneider 63598eb401dSValentin Schneider This requires the architecture to implement 636d4dbc991SVincent Guittot arch_update_hw_pressure() and arch_scale_thermal_pressure(). 63776504793SThara Gopinath 638391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT 63946329a9dSJeff Layton bool "BSD Process Accounting (DEPRECATED)" 6402813893fSIulia Manda depends on MULTIUSER 64146329a9dSJeff Layton default n 642391dc69cSFrederic Weisbecker help 643391dc69cSFrederic Weisbecker If you say Y here, a user level program will be able to instruct the 644391dc69cSFrederic Weisbecker kernel (via a special system call) to write process accounting 645391dc69cSFrederic Weisbecker information to a file: whenever a process exits, information about 646391dc69cSFrederic Weisbecker that process will be appended to the file by the kernel. The 647391dc69cSFrederic Weisbecker information includes things such as creation time, owning user, 648391dc69cSFrederic Weisbecker command name, memory usage, controlling terminal etc. (the complete 649391dc69cSFrederic Weisbecker list is in the struct acct in <file:include/linux/acct.h>). It is 650391dc69cSFrederic Weisbecker up to the user level program to do useful things with this 65146329a9dSJeff Layton information. This mechanism is antiquated and has significant 65246329a9dSJeff Layton scalability issues. You probably want to use eBPF instead. Say 65346329a9dSJeff Layton N unless you really need this. 654391dc69cSFrederic Weisbecker 655391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3 656391dc69cSFrederic Weisbecker bool "BSD Process Accounting version 3 file format" 657391dc69cSFrederic Weisbecker depends on BSD_PROCESS_ACCT 658391dc69cSFrederic Weisbecker default n 659391dc69cSFrederic Weisbecker help 660391dc69cSFrederic Weisbecker If you say Y here, the process accounting information is written 661391dc69cSFrederic Weisbecker in a new file format that also logs the process IDs of each 6623903bf94SRandy Dunlap process and its parent. Note that this file format is incompatible 663391dc69cSFrederic Weisbecker with previous v0/v1/v2 file formats, so you will need updated tools 664391dc69cSFrederic Weisbecker for processing it. A preliminary version of these tools is available 665391dc69cSFrederic Weisbecker at <http://www.gnu.org/software/acct/>. 666391dc69cSFrederic Weisbecker 667391dc69cSFrederic Weisbeckerconfig TASKSTATS 66819c92399SKees Cook bool "Export task/process statistics through netlink" 669391dc69cSFrederic Weisbecker depends on NET 6702813893fSIulia Manda depends on MULTIUSER 671391dc69cSFrederic Weisbecker default n 672391dc69cSFrederic Weisbecker help 673391dc69cSFrederic Weisbecker Export selected statistics for tasks/processes through the 674391dc69cSFrederic Weisbecker generic netlink interface. Unlike BSD process accounting, the 675391dc69cSFrederic Weisbecker statistics are available during the lifetime of tasks/processes as 676391dc69cSFrederic Weisbecker responses to commands. Like BSD accounting, they are sent to user 677391dc69cSFrederic Weisbecker space on task exit. 678391dc69cSFrederic Weisbecker 679391dc69cSFrederic Weisbecker Say N if unsure. 680391dc69cSFrederic Weisbecker 681391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT 68219c92399SKees Cook bool "Enable per-task delay accounting" 683391dc69cSFrederic Weisbecker depends on TASKSTATS 684f6db8347SNaveen N. Rao select SCHED_INFO 685391dc69cSFrederic Weisbecker help 686391dc69cSFrederic Weisbecker Collect information on time spent by a task waiting for system 687391dc69cSFrederic Weisbecker resources like cpu, synchronous block I/O completion and swapping 688391dc69cSFrederic Weisbecker in pages. Such statistics can help in setting a task's priorities 689391dc69cSFrederic Weisbecker relative to other tasks for cpu, io, rss limits etc. 690391dc69cSFrederic Weisbecker 691391dc69cSFrederic Weisbecker Say N if unsure. 692391dc69cSFrederic Weisbecker 693391dc69cSFrederic Weisbeckerconfig TASK_XACCT 69419c92399SKees Cook bool "Enable extended accounting over taskstats" 695391dc69cSFrederic Weisbecker depends on TASKSTATS 696391dc69cSFrederic Weisbecker help 697391dc69cSFrederic Weisbecker Collect extended task accounting data and send the data 698391dc69cSFrederic Weisbecker to userland for processing over the taskstats interface. 699391dc69cSFrederic Weisbecker 700391dc69cSFrederic Weisbecker Say N if unsure. 701391dc69cSFrederic Weisbecker 702391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING 70319c92399SKees Cook bool "Enable per-task storage I/O accounting" 704391dc69cSFrederic Weisbecker depends on TASK_XACCT 705391dc69cSFrederic Weisbecker help 706391dc69cSFrederic Weisbecker Collect information on the number of bytes of storage I/O which this 707391dc69cSFrederic Weisbecker task has caused. 708391dc69cSFrederic Weisbecker 709391dc69cSFrederic Weisbecker Say N if unsure. 710391dc69cSFrederic Weisbecker 711eb414681SJohannes Weinerconfig PSI 712eb414681SJohannes Weiner bool "Pressure stall information tracking" 71398dfdd9eSRandy Dunlap select KERNFS 714eb414681SJohannes Weiner help 715eb414681SJohannes Weiner Collect metrics that indicate how overcommitted the CPU, memory, 716eb414681SJohannes Weiner and IO capacity are in the system. 717eb414681SJohannes Weiner 718eb414681SJohannes Weiner If you say Y here, the kernel will create /proc/pressure/ with the 719eb414681SJohannes Weiner pressure statistics files cpu, memory, and io. These will indicate 720eb414681SJohannes Weiner the share of walltime in which some or all tasks in the system are 721eb414681SJohannes Weiner delayed due to contention of the respective resource. 722eb414681SJohannes Weiner 7232ce7135aSJohannes Weiner In kernels with cgroup support, cgroups (cgroup2 only) will 7242ce7135aSJohannes Weiner have cpu.pressure, memory.pressure, and io.pressure files, 7252ce7135aSJohannes Weiner which aggregate pressure stalls for the grouped tasks only. 7262ce7135aSJohannes Weiner 727c3123552SMauro Carvalho Chehab For more details see Documentation/accounting/psi.rst. 728eb414681SJohannes Weiner 729eb414681SJohannes Weiner Say N if unsure. 730eb414681SJohannes Weiner 731e0c27447SJohannes Weinerconfig PSI_DEFAULT_DISABLED 732e0c27447SJohannes Weiner bool "Require boot parameter to enable pressure stall information tracking" 733e0c27447SJohannes Weiner default n 734e0c27447SJohannes Weiner depends on PSI 735e0c27447SJohannes Weiner help 736e0c27447SJohannes Weiner If set, pressure stall information tracking will be disabled 737428a1cb4SBaruch Siach per default but can be enabled through passing psi=1 on the 738428a1cb4SBaruch Siach kernel commandline during boot. 739e0c27447SJohannes Weiner 7407b2489d3SJohannes Weiner This feature adds some code to the task wakeup and sleep 7417b2489d3SJohannes Weiner paths of the scheduler. The overhead is too low to affect 7427b2489d3SJohannes Weiner common scheduling-intense workloads in practice (such as 7437b2489d3SJohannes Weiner webservers, memcache), but it does show up in artificial 7447b2489d3SJohannes Weiner scheduler stress tests, such as hackbench. 7457b2489d3SJohannes Weiner 7467b2489d3SJohannes Weiner If you are paranoid and not sure what the kernel will be 7477b2489d3SJohannes Weiner used for, say Y. 7487b2489d3SJohannes Weiner 7497b2489d3SJohannes Weiner Say N if unsure. 7507b2489d3SJohannes Weiner 751391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting" 752391dc69cSFrederic Weisbecker 7535c4991e2SFrederic Weisbeckerconfig CPU_ISOLATION 7545c4991e2SFrederic Weisbecker bool "CPU isolation" 75597577684SOleg Nesterov depends on SMP 7562c43838cSFrederic Weisbecker default y 7575c4991e2SFrederic Weisbecker help 7585c4991e2SFrederic Weisbecker Make sure that CPUs running critical tasks are not disturbed by 7595c4991e2SFrederic Weisbecker any source of "noise" such as unbound workqueues, timers, kthreads... 7602c43838cSFrederic Weisbecker Unbound jobs get offloaded to housekeeping CPUs. This is driven by 7612c43838cSFrederic Weisbecker the "isolcpus=" boot parameter. 7622c43838cSFrederic Weisbecker 7632c43838cSFrederic Weisbecker Say Y if unsure. 7645c4991e2SFrederic Weisbecker 7650af92d46SPaul E. McKenneysource "kernel/rcu/Kconfig" 766c903ff83SMike Travis 7671da177e4SLinus Torvaldsconfig IKCONFIG 768f2443ab6SRoss Biro tristate "Kernel .config support" 769a7f7f624SMasahiro Yamada help 7701da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 7711da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 7721da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 7731da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 7741da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 7751da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 7761da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 7771da177e4SLinus Torvalds /proc/config.gz if enabled (below). 7781da177e4SLinus Torvalds 7791da177e4SLinus Torvaldsconfig IKCONFIG_PROC 7801da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 7811da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 782a7f7f624SMasahiro Yamada help 7831da177e4SLinus Torvalds This option enables access to the kernel configuration file 7841da177e4SLinus Torvalds through /proc/config.gz. 7851da177e4SLinus Torvalds 786f7b101d3SJoel Fernandes (Google)config IKHEADERS 787f7b101d3SJoel Fernandes (Google) tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 788f7b101d3SJoel Fernandes (Google) depends on SYSFS 78943d8ce9dSJoel Fernandes (Google) help 790f7b101d3SJoel Fernandes (Google) This option enables access to the in-kernel headers that are generated during 791f7b101d3SJoel Fernandes (Google) the build process. These can be used to build eBPF tracing programs, 792f7b101d3SJoel Fernandes (Google) or similar programs. If you build the headers as a module, a module called 793f7b101d3SJoel Fernandes (Google) kheaders.ko is built which can be loaded on-demand to get access to headers. 79443d8ce9dSJoel Fernandes (Google) 795794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 796794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 7971c4b5ecbSChristoph Hellwig range 12 25 798f17a32e9SAdrian Bunk default 17 799361e9dfbSJosh Triplett depends on PRINTK 800794543a2SAlistair John Strachan help 80123b2899fSLuis R. Rodriguez Select the minimal kernel log buffer size as a power of 2. 80223b2899fSLuis R. Rodriguez The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 80323b2899fSLuis R. Rodriguez parameter, see below. Any higher size also might be forced 80423b2899fSLuis R. Rodriguez by "log_buf_len" boot parameter. 80523b2899fSLuis R. Rodriguez 806f17a32e9SAdrian Bunk Examples: 807f17a32e9SAdrian Bunk 17 => 128 KB 808f17a32e9SAdrian Bunk 16 => 64 KB 809f17a32e9SAdrian Bunk 15 => 32 KB 810f17a32e9SAdrian Bunk 14 => 16 KB 811794543a2SAlistair John Strachan 13 => 8 KB 812794543a2SAlistair John Strachan 12 => 4 KB 813794543a2SAlistair John Strachan 81423b2899fSLuis R. Rodriguezconfig LOG_CPU_MAX_BUF_SHIFT 81523b2899fSLuis R. Rodriguez int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 8162240a31dSGeert Uytterhoeven depends on SMP 81723b2899fSLuis R. Rodriguez range 0 21 81823b2899fSLuis R. Rodriguez default 0 if BASE_SMALL 819320bf431SYoann Congal default 12 820361e9dfbSJosh Triplett depends on PRINTK 82123b2899fSLuis R. Rodriguez help 82223b2899fSLuis R. Rodriguez This option allows to increase the default ring buffer size 82323b2899fSLuis R. Rodriguez according to the number of CPUs. The value defines the contribution 82423b2899fSLuis R. Rodriguez of each CPU as a power of 2. The used space is typically only few 82523b2899fSLuis R. Rodriguez lines however it might be much more when problems are reported, 82623b2899fSLuis R. Rodriguez e.g. backtraces. 82723b2899fSLuis R. Rodriguez 82823b2899fSLuis R. Rodriguez The increased size means that a new buffer has to be allocated and 82923b2899fSLuis R. Rodriguez the original static one is unused. It makes sense only on systems 83023b2899fSLuis R. Rodriguez with more CPUs. Therefore this value is used only when the sum of 83123b2899fSLuis R. Rodriguez contributions is greater than the half of the default kernel ring 83223b2899fSLuis R. Rodriguez buffer as defined by LOG_BUF_SHIFT. The default values are set 8330f7636e1SPaul Menzel so that more than 16 CPUs are needed to trigger the allocation. 83423b2899fSLuis R. Rodriguez 83523b2899fSLuis R. Rodriguez Also this option is ignored when "log_buf_len" kernel parameter is 83623b2899fSLuis R. Rodriguez used as it forces an exact (power of two) size of the ring buffer. 83723b2899fSLuis R. Rodriguez 83823b2899fSLuis R. Rodriguez The number of possible CPUs is used for this computation ignoring 8395e0d8d59SGeert Uytterhoeven hotplugging making the computation optimal for the worst case 8405e0d8d59SGeert Uytterhoeven scenario while allowing a simple algorithm to be used from bootup. 84123b2899fSLuis R. Rodriguez 84223b2899fSLuis R. Rodriguez Examples shift values and their meaning: 84323b2899fSLuis R. Rodriguez 17 => 128 KB for each CPU 84423b2899fSLuis R. Rodriguez 16 => 64 KB for each CPU 84523b2899fSLuis R. Rodriguez 15 => 32 KB for each CPU 84623b2899fSLuis R. Rodriguez 14 => 16 KB for each CPU 84723b2899fSLuis R. Rodriguez 13 => 8 KB for each CPU 84823b2899fSLuis R. Rodriguez 12 => 4 KB for each CPU 84923b2899fSLuis R. Rodriguez 85033701557SChris Downconfig PRINTK_INDEX 85133701557SChris Down bool "Printk indexing debugfs interface" 85233701557SChris Down depends on PRINTK && DEBUG_FS 85333701557SChris Down help 85433701557SChris Down Add support for indexing of all printk formats known at compile time 85533701557SChris Down at <debugfs>/printk/index/<module>. 85633701557SChris Down 85733701557SChris Down This can be used as part of maintaining daemons which monitor 85833701557SChris Down /dev/kmsg, as it permits auditing the printk formats present in a 85933701557SChris Down kernel, allowing detection of cases where monitored printks are 86033701557SChris Down changed or no longer present. 86133701557SChris Down 86233701557SChris Down There is no additional runtime cost to printk with this enabled. 86333701557SChris Down 8645cdc38f9SKAMEZAWA Hiroyuki# 8655cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this: 8665cdc38f9SKAMEZAWA Hiroyuki# 8675cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK 8685cdc38f9SKAMEZAWA Hiroyuki bool 8695cdc38f9SKAMEZAWA Hiroyuki 87038ff87f7SStephen Boydconfig GENERIC_SCHED_CLOCK 87138ff87f7SStephen Boyd bool 87238ff87f7SStephen Boyd 87369842cbaSPatrick Bellasimenu "Scheduler features" 87469842cbaSPatrick Bellasi 87569842cbaSPatrick Bellasiconfig UCLAMP_TASK 87669842cbaSPatrick Bellasi bool "Enable utilization clamping for RT/FAIR tasks" 87769842cbaSPatrick Bellasi depends on CPU_FREQ_GOV_SCHEDUTIL 87869842cbaSPatrick Bellasi help 87969842cbaSPatrick Bellasi This feature enables the scheduler to track the clamped utilization 88069842cbaSPatrick Bellasi of each CPU based on RUNNABLE tasks scheduled on that CPU. 88169842cbaSPatrick Bellasi 88269842cbaSPatrick Bellasi With this option, the user can specify the min and max CPU 88369842cbaSPatrick Bellasi utilization allowed for RUNNABLE tasks. The max utilization defines 88469842cbaSPatrick Bellasi the maximum frequency a task should use while the min utilization 88569842cbaSPatrick Bellasi defines the minimum frequency it should use. 88669842cbaSPatrick Bellasi 88769842cbaSPatrick Bellasi Both min and max utilization clamp values are hints to the scheduler, 88869842cbaSPatrick Bellasi aiming at improving its frequency selection policy, but they do not 88969842cbaSPatrick Bellasi enforce or grant any specific bandwidth for tasks. 89069842cbaSPatrick Bellasi 89169842cbaSPatrick Bellasi If in doubt, say N. 89269842cbaSPatrick Bellasi 89369842cbaSPatrick Bellasiconfig UCLAMP_BUCKETS_COUNT 89469842cbaSPatrick Bellasi int "Number of supported utilization clamp buckets" 89569842cbaSPatrick Bellasi range 5 20 89669842cbaSPatrick Bellasi default 5 89769842cbaSPatrick Bellasi depends on UCLAMP_TASK 89869842cbaSPatrick Bellasi help 89969842cbaSPatrick Bellasi Defines the number of clamp buckets to use. The range of each bucket 90069842cbaSPatrick Bellasi will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 90169842cbaSPatrick Bellasi number of clamp buckets the finer their granularity and the higher 90269842cbaSPatrick Bellasi the precision of clamping aggregation and tracking at run-time. 90369842cbaSPatrick Bellasi 90469842cbaSPatrick Bellasi For example, with the minimum configuration value we will have 5 90569842cbaSPatrick Bellasi clamp buckets tracking 20% utilization each. A 25% boosted tasks will 90669842cbaSPatrick Bellasi be refcounted in the [20..39]% bucket and will set the bucket clamp 90769842cbaSPatrick Bellasi effective value to 25%. 90869842cbaSPatrick Bellasi If a second 30% boosted task should be co-scheduled on the same CPU, 90969842cbaSPatrick Bellasi that task will be refcounted in the same bucket of the first task and 91069842cbaSPatrick Bellasi it will boost the bucket clamp effective value to 30%. 91169842cbaSPatrick Bellasi The clamp effective value of a bucket is reset to its nominal value 91269842cbaSPatrick Bellasi (20% in the example above) when there are no more tasks refcounted in 91369842cbaSPatrick Bellasi that bucket. 91469842cbaSPatrick Bellasi 91569842cbaSPatrick Bellasi An additional boost/capping margin can be added to some tasks. In the 91669842cbaSPatrick Bellasi example above the 25% task will be boosted to 30% until it exits the 91769842cbaSPatrick Bellasi CPU. If that should be considered not acceptable on certain systems, 91869842cbaSPatrick Bellasi it's always possible to reduce the margin by increasing the number of 91969842cbaSPatrick Bellasi clamp buckets to trade off used memory for run-time tracking 92069842cbaSPatrick Bellasi precision. 92169842cbaSPatrick Bellasi 92269842cbaSPatrick Bellasi If in doubt, use the default value. 92369842cbaSPatrick Bellasi 92425c411fcSJohn Stultzconfig SCHED_PROXY_EXEC 92525c411fcSJohn Stultz bool "Proxy Execution" 92625c411fcSJohn Stultz # Avoid some build failures w/ PREEMPT_RT until it can be fixed 92725c411fcSJohn Stultz depends on !PREEMPT_RT 92825c411fcSJohn Stultz # Need to investigate how to inform sched_ext of split contexts 92925c411fcSJohn Stultz depends on !SCHED_CLASS_EXT 93025c411fcSJohn Stultz # Not particularly useful until we get to multi-rq proxying 93125c411fcSJohn Stultz depends on EXPERT 93225c411fcSJohn Stultz help 93325c411fcSJohn Stultz This option enables proxy execution, a mechanism for mutex-owning 93425c411fcSJohn Stultz tasks to inherit the scheduling context of higher priority waiters. 93525c411fcSJohn Stultz 93669842cbaSPatrick Bellasiendmenu 93769842cbaSPatrick Bellasi 938be3a7284SAndrea Arcangeli# 939be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler 940be3a7284SAndrea Arcangeli# balancing logic: 941be3a7284SAndrea Arcangeli# 942be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING 943be3a7284SAndrea Arcangeli bool 944be3a7284SAndrea Arcangeli 945be5e610cSPeter Zijlstra# 94672b252aeSMel Gorman# For architectures that prefer to flush all TLBs after a number of pages 94772b252aeSMel Gorman# are unmapped instead of sending one IPI per page to flush. The architecture 94872b252aeSMel Gorman# must provide guarantees on what happens if a clean TLB cache entry is 94972b252aeSMel Gorman# written after the unmap. Details are in mm/rmap.c near the check for 95072b252aeSMel Gorman# should_defer_flush. The architecture should also consider if the full flush 95172b252aeSMel Gorman# and the refill costs are offset by the savings of sending fewer IPIs. 95272b252aeSMel Gormanconfig ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 95372b252aeSMel Gorman bool 95472b252aeSMel Gorman 955c12d3362SArd Biesheuvelconfig CC_HAS_INT128 9563a7c7331SMasahiro Yamada def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 957c12d3362SArd Biesheuvel 958dee2b702SGustavo A. R. Silvaconfig CC_IMPLICIT_FALLTHROUGH 959dee2b702SGustavo A. R. Silva string 960158ea2d2SGustavo A. R. Silva default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 961dee2b702SGustavo A. R. Silva default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 962dee2b702SGustavo A. R. Silva 9633e00f580SKees Cook# Currently, disable gcc-10+ array-bounds globally. 9640da6e5fdSLinus Torvalds# It's still broken in gcc-13, so no upper bound yet. 9653e00f580SKees Cookconfig GCC10_NO_ARRAY_BOUNDS 9665a41237aSLinus Torvalds def_bool y 9675a41237aSLinus Torvalds 968f0be87c4SLinus Torvaldsconfig CC_NO_ARRAY_BOUNDS 969f0be87c4SLinus Torvalds bool 9708e5bd4eaSYury Norov default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 971f0be87c4SLinus Torvalds 97202153319SLinus Torvalds# Currently, disable -Wstringop-overflow for GCC globally. 97302153319SLinus Torvaldsconfig GCC_NO_STRINGOP_OVERFLOW 974a5e0ace0SGustavo A. R. Silva def_bool y 975a5e0ace0SGustavo A. R. Silva 976a5e0ace0SGustavo A. R. Silvaconfig CC_NO_STRINGOP_OVERFLOW 977a5e0ace0SGustavo A. R. Silva bool 97802153319SLinus Torvalds default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 979a5e0ace0SGustavo A. R. Silva 980a5e0ace0SGustavo A. R. Silvaconfig CC_STRINGOP_OVERFLOW 981a5e0ace0SGustavo A. R. Silva bool 982a5e0ace0SGustavo A. R. Silva default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 983a5e0ace0SGustavo A. R. Silva 98472b252aeSMel Gorman# 985be5e610cSPeter Zijlstra# For architectures that know their GCC __int128 support is sound 986be5e610cSPeter Zijlstra# 987be5e610cSPeter Zijlstraconfig ARCH_SUPPORTS_INT128 988be5e610cSPeter Zijlstra bool 989be5e610cSPeter Zijlstra 990be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions 991be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH. 992be3a7284SAndrea Arcangeli# 993be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY 994be3a7284SAndrea Arcangeli bool 995be3a7284SAndrea Arcangeli 996be3a7284SAndrea Arcangeliconfig NUMA_BALANCING 997be3a7284SAndrea Arcangeli bool "Memory placement aware NUMA scheduler" 998be3a7284SAndrea Arcangeli depends on ARCH_SUPPORTS_NUMA_BALANCING 999be3a7284SAndrea Arcangeli depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 1000554b0f3cSSebastian Andrzej Siewior depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 1001be3a7284SAndrea Arcangeli help 1002be3a7284SAndrea Arcangeli This option adds support for automatic NUMA aware memory/task placement. 1003be3a7284SAndrea Arcangeli The mechanism is quite primitive and is based on migrating memory when 10046d56a410SPaul Gortmaker it has references to the node the task is running on. 1005be3a7284SAndrea Arcangeli 1006be3a7284SAndrea Arcangeli This system will be inactive on UMA systems. 1007be3a7284SAndrea Arcangeli 10086f7c97e8SAneesh Kumar K.Vconfig NUMA_BALANCING_DEFAULT_ENABLED 10096f7c97e8SAneesh Kumar K.V bool "Automatically enable NUMA aware memory/task placement" 10106f7c97e8SAneesh Kumar K.V default y 10116f7c97e8SAneesh Kumar K.V depends on NUMA_BALANCING 10126f7c97e8SAneesh Kumar K.V help 10136f7c97e8SAneesh Kumar K.V If set, automatic NUMA balancing will be enabled if running on a NUMA 10146f7c97e8SAneesh Kumar K.V machine. 10156f7c97e8SAneesh Kumar K.V 101621c690a3SSuren Baghdasaryanconfig SLAB_OBJ_EXT 101721c690a3SSuren Baghdasaryan bool 101821c690a3SSuren Baghdasaryan 101923964d2dSLi Zefanmenuconfig CGROUPS 10206341e62bSChristoph Jaeger bool "Control Group support" 10212bd59d48STejun Heo select KERNFS 1022ddbcc7e8SPaul Menage help 102323964d2dSLi Zefan This option adds support for grouping sets of processes together, for 10245cdc38f9SKAMEZAWA Hiroyuki use with process control subsystems such as Cpusets, CFS, memory 10255cdc38f9SKAMEZAWA Hiroyuki controls or device isolation. 10265cdc38f9SKAMEZAWA Hiroyuki See 1027d6a3b247SMauro Carvalho Chehab - Documentation/scheduler/sched-design-CFS.rst (CFS) 1028da82c92fSMauro Carvalho Chehab - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 102945ce80fbSLi Zefan and resource control) 1030ddbcc7e8SPaul Menage 1031ddbcc7e8SPaul Menage Say N if unsure. 1032ddbcc7e8SPaul Menage 103323964d2dSLi Zefanif CGROUPS 103423964d2dSLi Zefan 10353e32cb2eSJohannes Weinerconfig PAGE_COUNTER 10363e32cb2eSJohannes Weiner bool 10373e32cb2eSJohannes Weiner 10386a010a49STejun Heoconfig CGROUP_FAVOR_DYNMODS 10396a010a49STejun Heo bool "Favor dynamic modification latency reduction by default" 10406a010a49STejun Heo help 10416a010a49STejun Heo This option enables the "favordynmods" mount option by default 10426a010a49STejun Heo which reduces the latencies of dynamic cgroup modifications such 10436a010a49STejun Heo as task migrations and controller on/offs at the cost of making 10446a010a49STejun Heo hot path operations such as forks and exits more expensive. 10456a010a49STejun Heo 10466a010a49STejun Heo Say N if unsure. 10476a010a49STejun Heo 1048c255a458SAndrew Mortonconfig MEMCG 1049a0166ec4SJohannes Weiner bool "Memory controller" 10503e32cb2eSJohannes Weiner select PAGE_COUNTER 105179bd9814STejun Heo select EVENTFD 105221c690a3SSuren Baghdasaryan select SLAB_OBJ_EXT 1053fdc5001bSKirill A. Shutemov select VM_EVENT_COUNTERS 105400f0b825SBalbir Singh help 1055a0166ec4SJohannes Weiner Provides control over the memory footprint of tasks in a cgroup. 105600f0b825SBalbir Singh 105725352d2fSShakeel Buttconfig MEMCG_NMI_UNSAFE 105825352d2fSShakeel Butt bool 105925352d2fSShakeel Butt depends on MEMCG 106025352d2fSShakeel Butt depends on HAVE_NMI 106125352d2fSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 106225352d2fSShakeel Butt default y 106325352d2fSShakeel Butt 1064940b01fcSShakeel Buttconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1065940b01fcSShakeel Butt bool 1066940b01fcSShakeel Butt depends on MEMCG 1067940b01fcSShakeel Butt depends on HAVE_NMI 1068940b01fcSShakeel Butt depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1069940b01fcSShakeel Butt default y 1070940b01fcSShakeel Butt 1071e93d4166SRoman Gushchinconfig MEMCG_V1 1072e93d4166SRoman Gushchin bool "Legacy cgroup v1 memory controller" 1073c9929f0eSVlastimil Babka depends on MEMCG 1074e93d4166SRoman Gushchin default n 1075e93d4166SRoman Gushchin help 1076e93d4166SRoman Gushchin Legacy cgroup v1 memory controller which has been deprecated by 1077e93d4166SRoman Gushchin cgroup v2 implementation. The v1 is there for legacy applications 1078e93d4166SRoman Gushchin which haven't migrated to the new cgroup v2 interface yet. If you 1079e93d4166SRoman Gushchin do not have any such application then you are completely fine leaving 1080e93d4166SRoman Gushchin this option disabled. 1081e93d4166SRoman Gushchin 1082e93d4166SRoman Gushchin Please note that feature set of the legacy memory controller is likely 1083e93d4166SRoman Gushchin going to shrink due to deprecation process. New deployments with v1 1084e93d4166SRoman Gushchin controller are highly discouraged. 1085e93d4166SRoman Gushchin 1086fcb4824bSValdis Kletnieks Say N if unsure. 108784c07d11SKirill Tkhai 10886bf024e6SJohannes Weinerconfig BLK_CGROUP 10896bf024e6SJohannes Weiner bool "IO controller" 10906bf024e6SJohannes Weiner depends on BLOCK 10912bc64a20SAneesh Kumar K.V default n 1092a7f7f624SMasahiro Yamada help 10936bf024e6SJohannes Weiner Generic block IO controller cgroup interface. This is the common 10946bf024e6SJohannes Weiner cgroup interface which should be used by various IO controlling 10956bf024e6SJohannes Weiner policies. 10962bc64a20SAneesh Kumar K.V 10976bf024e6SJohannes Weiner Currently, CFQ IO scheduler uses it to recognize task groups and 10986bf024e6SJohannes Weiner control disk bandwidth allocation (proportional time slice allocation) 10996bf024e6SJohannes Weiner to such task groups. It is also used by bio throttling logic in 11006bf024e6SJohannes Weiner block layer to implement upper limit in IO rates on a device. 1101e5d1367fSStephane Eranian 11026bf024e6SJohannes Weiner This option only enables generic Block IO controller infrastructure. 11036bf024e6SJohannes Weiner One needs to also enable actual IO controlling logic/policy. For 11046bf024e6SJohannes Weiner enabling proportional weight division of disk bandwidth in CFQ, set 11057baf2199SKrzysztof Kozlowski CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 11066bf024e6SJohannes Weiner CONFIG_BLK_DEV_THROTTLING=y. 11076bf024e6SJohannes Weiner 1108da82c92fSMauro Carvalho Chehab See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 11096bf024e6SJohannes Weiner 11106bf024e6SJohannes Weinerconfig CGROUP_WRITEBACK 11116bf024e6SJohannes Weiner bool 11126bf024e6SJohannes Weiner depends on MEMCG && BLK_CGROUP 11136bf024e6SJohannes Weiner default y 1114e5d1367fSStephane Eranian 11157c941438SDhaval Gianimenuconfig CGROUP_SCHED 1116a0166ec4SJohannes Weiner bool "CPU controller" 11177c941438SDhaval Giani default n 11187c941438SDhaval Giani help 11197c941438SDhaval Giani This feature lets CPU scheduler recognize task groups and control CPU 11207c941438SDhaval Giani bandwidth allocation to such task groups. It uses cgroups to group 11217c941438SDhaval Giani tasks. 11227c941438SDhaval Giani 11237c941438SDhaval Gianiif CGROUP_SCHED 1124e179e80cSTejun Heoconfig GROUP_SCHED_WEIGHT 1125e179e80cSTejun Heo def_bool n 1126e179e80cSTejun Heo 1127ddceadceSTejun Heoconfig GROUP_SCHED_BANDWIDTH 1128ddceadceSTejun Heo def_bool n 1129ddceadceSTejun Heo 11307c941438SDhaval Gianiconfig FAIR_GROUP_SCHED 11317c941438SDhaval Giani bool "Group scheduling for SCHED_OTHER" 11327c941438SDhaval Giani depends on CGROUP_SCHED 1133e179e80cSTejun Heo select GROUP_SCHED_WEIGHT 11347c941438SDhaval Giani default CGROUP_SCHED 11357c941438SDhaval Giani 1136ab84d31eSPaul Turnerconfig CFS_BANDWIDTH 1137ab84d31eSPaul Turner bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1138ab84d31eSPaul Turner depends on FAIR_GROUP_SCHED 1139ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 1140ab84d31eSPaul Turner default n 1141ab84d31eSPaul Turner help 1142ab84d31eSPaul Turner This option allows users to define CPU bandwidth rates (limits) for 1143ab84d31eSPaul Turner tasks running within the fair group scheduler. Groups with no limit 1144ab84d31eSPaul Turner set are considered to be unconstrained and will run with no 1145ab84d31eSPaul Turner restriction. 1146d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-bwc.rst for more information. 1147ab84d31eSPaul Turner 11487c941438SDhaval Gianiconfig RT_GROUP_SCHED 11497c941438SDhaval Giani bool "Group scheduling for SCHED_RR/FIFO" 11507c941438SDhaval Giani depends on CGROUP_SCHED 11517c941438SDhaval Giani default n 11527c941438SDhaval Giani help 11537c941438SDhaval Giani This feature lets you explicitly allocate real CPU bandwidth 115432bd7eb5SLi Zefan to task groups. If enabled, it will also make it impossible to 11557c941438SDhaval Giani schedule realtime tasks for non-root users until you allocate 11567c941438SDhaval Giani realtime bandwidth for them. 1157d6a3b247SMauro Carvalho Chehab See Documentation/scheduler/sched-rt-group.rst for more information. 11587c941438SDhaval Giani 1159e34e0131SMichal Koutnýconfig RT_GROUP_SCHED_DEFAULT_DISABLED 1160e34e0131SMichal Koutný bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1161e34e0131SMichal Koutný depends on RT_GROUP_SCHED 1162e34e0131SMichal Koutný default n 1163e34e0131SMichal Koutný help 1164e34e0131SMichal Koutný When set, the RT group scheduling is disabled by default. The option 1165e34e0131SMichal Koutný is in inverted form so that mere RT_GROUP_SCHED enables the group 1166e34e0131SMichal Koutný scheduling. 1167e34e0131SMichal Koutný 1168e34e0131SMichal Koutný Say N if unsure. 1169e34e0131SMichal Koutný 117081951366STejun Heoconfig EXT_GROUP_SCHED 117181951366STejun Heo bool 117281951366STejun Heo depends on SCHED_CLASS_EXT && CGROUP_SCHED 117381951366STejun Heo select GROUP_SCHED_WEIGHT 1174ddceadceSTejun Heo select GROUP_SCHED_BANDWIDTH 117581951366STejun Heo default y 117681951366STejun Heo 11777c941438SDhaval Gianiendif #CGROUP_SCHED 11787c941438SDhaval Giani 1179af7f588dSMathieu Desnoyersconfig SCHED_MM_CID 1180af7f588dSMathieu Desnoyers def_bool y 1181af7f588dSMathieu Desnoyers depends on SMP && RSEQ 1182af7f588dSMathieu Desnoyers 11832480c093SPatrick Bellasiconfig UCLAMP_TASK_GROUP 11842480c093SPatrick Bellasi bool "Utilization clamping per group of tasks" 11852480c093SPatrick Bellasi depends on CGROUP_SCHED 11862480c093SPatrick Bellasi depends on UCLAMP_TASK 11872480c093SPatrick Bellasi default n 11882480c093SPatrick Bellasi help 11892480c093SPatrick Bellasi This feature enables the scheduler to track the clamped utilization 11902480c093SPatrick Bellasi of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 11912480c093SPatrick Bellasi 11922480c093SPatrick Bellasi When this option is enabled, the user can specify a min and max 11932480c093SPatrick Bellasi CPU bandwidth which is allowed for each single task in a group. 11942480c093SPatrick Bellasi The max bandwidth allows to clamp the maximum frequency a task 11952480c093SPatrick Bellasi can use, while the min bandwidth allows to define a minimum 11962480c093SPatrick Bellasi frequency a task will always use. 11972480c093SPatrick Bellasi 11982480c093SPatrick Bellasi When task group based utilization clamping is enabled, an eventually 11992480c093SPatrick Bellasi specified task-specific clamp value is constrained by the cgroup 12002480c093SPatrick Bellasi specified clamp value. Both minimum and maximum task clamping cannot 12012480c093SPatrick Bellasi be bigger than the corresponding clamping defined at task group level. 12022480c093SPatrick Bellasi 12032480c093SPatrick Bellasi If in doubt, say N. 12042480c093SPatrick Bellasi 12056bf024e6SJohannes Weinerconfig CGROUP_PIDS 12066bf024e6SJohannes Weiner bool "PIDs controller" 12076bf024e6SJohannes Weiner help 12086bf024e6SJohannes Weiner Provides enforcement of process number limits in the scope of a 12096bf024e6SJohannes Weiner cgroup. Any attempt to fork more processes than is allowed in the 12106bf024e6SJohannes Weiner cgroup will fail. PIDs are fundamentally a global resource because it 12116bf024e6SJohannes Weiner is fairly trivial to reach PID exhaustion before you reach even a 12126bf024e6SJohannes Weiner conservative kmemcg limit. As a result, it is possible to grind a 12136bf024e6SJohannes Weiner system to halt without being limited by other cgroup policies. The 12146cc578dfSParav Pandit PIDs controller is designed to stop this from happening. 12156bf024e6SJohannes Weiner 12166bf024e6SJohannes Weiner It should be noted that organisational operations (such as attaching 121798076833SJonathan Neuschäfer to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 12186bf024e6SJohannes Weiner since the PIDs limit only affects a process's ability to fork, not to 12196bf024e6SJohannes Weiner attach to a cgroup. 12206bf024e6SJohannes Weiner 122139d3e758SParav Panditconfig CGROUP_RDMA 122239d3e758SParav Pandit bool "RDMA controller" 122339d3e758SParav Pandit help 122439d3e758SParav Pandit Provides enforcement of RDMA resources defined by IB stack. 122539d3e758SParav Pandit It is fairly easy for consumers to exhaust RDMA resources, which 122639d3e758SParav Pandit can result into resource unavailability to other consumers. 122739d3e758SParav Pandit RDMA controller is designed to stop this from happening. 122839d3e758SParav Pandit Attaching processes with active RDMA resources to the cgroup 122939d3e758SParav Pandit hierarchy is allowed even if can cross the hierarchy's limit. 123039d3e758SParav Pandit 1231b168ed45SMaarten Lankhorstconfig CGROUP_DMEM 1232b168ed45SMaarten Lankhorst bool "Device memory controller (DMEM)" 1233e33b5149SMaxime Ripard select PAGE_COUNTER 1234b168ed45SMaarten Lankhorst help 1235b168ed45SMaarten Lankhorst The DMEM controller allows compatible devices to restrict device 1236b168ed45SMaarten Lankhorst memory usage based on the cgroup hierarchy. 1237b168ed45SMaarten Lankhorst 1238b168ed45SMaarten Lankhorst As an example, it allows you to restrict VRAM usage for applications 1239b168ed45SMaarten Lankhorst in the DRM subsystem. 1240b168ed45SMaarten Lankhorst 12416bf024e6SJohannes Weinerconfig CGROUP_FREEZER 12426bf024e6SJohannes Weiner bool "Freezer controller" 12436bf024e6SJohannes Weiner help 12446bf024e6SJohannes Weiner Provides a way to freeze and unfreeze all tasks in a 12456bf024e6SJohannes Weiner cgroup. 12466bf024e6SJohannes Weiner 1247489c2a20SJohannes Weiner This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1248489c2a20SJohannes Weiner controller includes important in-kernel memory consumers per default. 1249489c2a20SJohannes Weiner 1250489c2a20SJohannes Weiner If you're using cgroup2, say N. 1251489c2a20SJohannes Weiner 12526bf024e6SJohannes Weinerconfig CGROUP_HUGETLB 12536bf024e6SJohannes Weiner bool "HugeTLB controller" 12546bf024e6SJohannes Weiner depends on HUGETLB_PAGE 12556bf024e6SJohannes Weiner select PAGE_COUNTER 1256afc24d49SVivek Goyal default n 12576bf024e6SJohannes Weiner help 12586bf024e6SJohannes Weiner Provides a cgroup controller for HugeTLB pages. 12596bf024e6SJohannes Weiner When you enable this, you can put a per cgroup limit on HugeTLB usage. 12606bf024e6SJohannes Weiner The limit is enforced during page fault. Since HugeTLB doesn't 12616bf024e6SJohannes Weiner support page reclaim, enforcing the limit at page fault time implies 12626bf024e6SJohannes Weiner that, the application will get SIGBUS signal if it tries to access 12636bf024e6SJohannes Weiner HugeTLB pages beyond its limit. This requires the application to know 12646bf024e6SJohannes Weiner beforehand how much HugeTLB pages it would require for its use. The 12656bf024e6SJohannes Weiner control group is tracked in the third page lru pointer. This means 12666bf024e6SJohannes Weiner that we cannot use the controller with huge page less than 3 pages. 1267afc24d49SVivek Goyal 12686bf024e6SJohannes Weinerconfig CPUSETS 12696bf024e6SJohannes Weiner bool "Cpuset controller" 1270e1d4eeecSNicolas Pitre depends on SMP 1271bf9850f6SKuan-Wei Chiu select UNION_FIND 127223f09dccSFrederic Weisbecker select CPU_ISOLATION 12736bf024e6SJohannes Weiner help 12746bf024e6SJohannes Weiner This option will let you create and manage CPUSETs which 12756bf024e6SJohannes Weiner allow dynamically partitioning a system into sets of CPUs and 12766bf024e6SJohannes Weiner Memory Nodes and assigning tasks to run only within those sets. 12776bf024e6SJohannes Weiner This is primarily useful on large SMP or NUMA systems. 1278afc24d49SVivek Goyal 12796bf024e6SJohannes Weiner Say N if unsure. 1280afc24d49SVivek Goyal 12811abab1baSChen Ridongconfig CPUSETS_V1 12821abab1baSChen Ridong bool "Legacy cgroup v1 cpusets controller" 12831abab1baSChen Ridong depends on CPUSETS 12841abab1baSChen Ridong default n 12851abab1baSChen Ridong help 12861abab1baSChen Ridong Legacy cgroup v1 cpusets controller which has been deprecated by 12871abab1baSChen Ridong cgroup v2 implementation. The v1 is there for legacy applications 1288dae68fbaSMichal Koutný which haven't migrated to the new cgroup v2 interface yet. Legacy 1289dae68fbaSMichal Koutný interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 12901abab1baSChen Ridong do not have any such application then you are completely fine leaving 12911abab1baSChen Ridong this option disabled. 12921abab1baSChen Ridong 12931abab1baSChen Ridong Say N if unsure. 12941abab1baSChen Ridong 12956bf024e6SJohannes Weinerconfig PROC_PID_CPUSET 12966bf024e6SJohannes Weiner bool "Include legacy /proc/<pid>/cpuset file" 1297dae68fbaSMichal Koutný depends on CPUSETS_V1 129889e9b9e0STejun Heo default y 129989e9b9e0STejun Heo 13006bf024e6SJohannes Weinerconfig CGROUP_DEVICE 13016bf024e6SJohannes Weiner bool "Device controller" 13026bf024e6SJohannes Weiner help 13036bf024e6SJohannes Weiner Provides a cgroup controller implementing whitelists for 13046bf024e6SJohannes Weiner devices which a process in the cgroup can mknod or open. 13056bf024e6SJohannes Weiner 13066bf024e6SJohannes Weinerconfig CGROUP_CPUACCT 13076bf024e6SJohannes Weiner bool "Simple CPU accounting controller" 13086bf024e6SJohannes Weiner help 13096bf024e6SJohannes Weiner Provides a simple controller for monitoring the 13106bf024e6SJohannes Weiner total CPU consumed by the tasks in a cgroup. 13116bf024e6SJohannes Weiner 13126bf024e6SJohannes Weinerconfig CGROUP_PERF 13136bf024e6SJohannes Weiner bool "Perf controller" 13146bf024e6SJohannes Weiner depends on PERF_EVENTS 13156bf024e6SJohannes Weiner help 13166bf024e6SJohannes Weiner This option extends the perf per-cpu mode to restrict monitoring 13176bf024e6SJohannes Weiner to threads which belong to the cgroup specified and run on the 13186546b19fSNamhyung Kim designated cpu. Or this can be used to have cgroup ID in samples 13196546b19fSNamhyung Kim so that it can monitor performance events among cgroups. 13206bf024e6SJohannes Weiner 13216bf024e6SJohannes Weiner Say N if unsure. 13226bf024e6SJohannes Weiner 132330070984SDaniel Mackconfig CGROUP_BPF 132430070984SDaniel Mack bool "Support for eBPF programs attached to cgroups" 1325483c4933SAndy Lutomirski depends on BPF_SYSCALL 1326483c4933SAndy Lutomirski select SOCK_CGROUP_DATA 132730070984SDaniel Mack help 132830070984SDaniel Mack Allow attaching eBPF programs to a cgroup using the bpf(2) 132930070984SDaniel Mack syscall command BPF_PROG_ATTACH. 133030070984SDaniel Mack 133130070984SDaniel Mack In which context these programs are accessed depends on the type 133230070984SDaniel Mack of attachment. For instance, programs that are attached using 133330070984SDaniel Mack BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 133430070984SDaniel Mack inet sockets. 133530070984SDaniel Mack 1336a72232eaSVipin Sharmaconfig CGROUP_MISC 1337a72232eaSVipin Sharma bool "Misc resource controller" 1338a72232eaSVipin Sharma default n 1339a72232eaSVipin Sharma help 1340a72232eaSVipin Sharma Provides a controller for miscellaneous resources on a host. 1341a72232eaSVipin Sharma 1342a72232eaSVipin Sharma Miscellaneous scalar resources are the resources on the host system 1343a72232eaSVipin Sharma which cannot be abstracted like the other cgroups. This controller 1344a72232eaSVipin Sharma tracks and limits the miscellaneous resources used by a process 1345a72232eaSVipin Sharma attached to a cgroup hierarchy. 1346a72232eaSVipin Sharma 1347a72232eaSVipin Sharma For more information, please check misc cgroup section in 1348a72232eaSVipin Sharma /Documentation/admin-guide/cgroup-v2.rst. 1349a72232eaSVipin Sharma 13506bf024e6SJohannes Weinerconfig CGROUP_DEBUG 135123b0be48SWaiman Long bool "Debug controller" 13526bf024e6SJohannes Weiner default n 135323b0be48SWaiman Long depends on DEBUG_KERNEL 13546bf024e6SJohannes Weiner help 13556bf024e6SJohannes Weiner This option enables a simple controller that exports 135623b0be48SWaiman Long debugging information about the cgroups framework. This 135723b0be48SWaiman Long controller is for control cgroup debugging only. Its 135823b0be48SWaiman Long interfaces are not stable. 13596bf024e6SJohannes Weiner 13606bf024e6SJohannes Weiner Say N. 13616bf024e6SJohannes Weiner 136273b35147SArnd Bergmannconfig SOCK_CGROUP_DATA 136373b35147SArnd Bergmann bool 136473b35147SArnd Bergmann default n 136573b35147SArnd Bergmann 136623964d2dSLi Zefanendif # CGROUPS 1367c077719bSKAMEZAWA Hiroyuki 13688dd2a82cSDaniel Lezcanomenuconfig NAMESPACES 13696a108a14SDavid Rientjes bool "Namespaces support" if EXPERT 13702813893fSIulia Manda depends on MULTIUSER 13716a108a14SDavid Rientjes default !EXPERT 1372c5289a69SPavel Emelyanov help 1373c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 1374c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 1375c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 1376c5289a69SPavel Emelyanov different namespaces. 1377c5289a69SPavel Emelyanov 13788dd2a82cSDaniel Lezcanoif NAMESPACES 13798dd2a82cSDaniel Lezcano 138058bfdd6dSPavel Emelyanovconfig UTS_NS 138158bfdd6dSPavel Emelyanov bool "UTS namespace" 138217a6d441SDaniel Lezcano default y 138358bfdd6dSPavel Emelyanov help 138458bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 138558bfdd6dSPavel Emelyanov uname() system call 138658bfdd6dSPavel Emelyanov 1387769071acSAndrei Vaginconfig TIME_NS 1388769071acSAndrei Vagin bool "TIME namespace" 1389bad53ae2SThomas Weißschuh depends on GENERIC_GETTIMEOFDAY 1390769071acSAndrei Vagin default y 1391769071acSAndrei Vagin help 1392769071acSAndrei Vagin In this namespace boottime and monotonic clocks can be set. 1393769071acSAndrei Vagin The time will keep going with the same pace. 1394769071acSAndrei Vagin 1395ae5e1b22SPavel Emelyanovconfig IPC_NS 1396ae5e1b22SPavel Emelyanov bool "IPC namespace" 13978dd2a82cSDaniel Lezcano depends on (SYSVIPC || POSIX_MQUEUE) 139817a6d441SDaniel Lezcano default y 1399ae5e1b22SPavel Emelyanov help 1400ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 1401614b84cfSSerge E. Hallyn different IPC objects in different namespaces. 1402ae5e1b22SPavel Emelyanov 1403aee16ce7SPavel Emelyanovconfig USER_NS 140419c92399SKees Cook bool "User namespace" 14055673a94cSEric W. Biederman default n 1406aee16ce7SPavel Emelyanov help 1407aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 1408aee16ce7SPavel Emelyanov to provide different user info for different servers. 1409e11f0ae3SEric W. Biederman 1410e11f0ae3SEric W. Biederman When user namespaces are enabled in the kernel it is 1411d886f4e4SJohannes Weiner recommended that the MEMCG option also be enabled and that 1412d886f4e4SJohannes Weiner user-space use the memory control groups to limit the amount 1413d886f4e4SJohannes Weiner of memory a memory unprivileged users can use. 1414e11f0ae3SEric W. Biederman 1415aee16ce7SPavel Emelyanov If unsure, say N. 1416aee16ce7SPavel Emelyanov 141774bd59bbSPavel Emelyanovconfig PID_NS 14189bd38c2cSDaniel Lezcano bool "PID Namespaces" 141917a6d441SDaniel Lezcano default y 142074bd59bbSPavel Emelyanov help 142112d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 1422692105b8SMatt LaPlante processes with the same pid as long as they are in different 142374bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 142474bd59bbSPavel Emelyanov 1425d6eb633fSMatt Helsleyconfig NET_NS 1426d6eb633fSMatt Helsley bool "Network namespace" 14278dd2a82cSDaniel Lezcano depends on NET 142817a6d441SDaniel Lezcano default y 1429d6eb633fSMatt Helsley help 1430d6eb633fSMatt Helsley Allow user space to create what appear to be multiple instances 1431d6eb633fSMatt Helsley of the network stack. 1432d6eb633fSMatt Helsley 14338dd2a82cSDaniel Lezcanoendif # NAMESPACES 14348dd2a82cSDaniel Lezcano 14355cb366bbSAdrian Reberconfig CHECKPOINT_RESTORE 14365cb366bbSAdrian Reber bool "Checkpoint/restore support" 143730341ec9SRen Zhijie depends on PROC_FS 14385cb366bbSAdrian Reber select PROC_CHILDREN 1439bfe3911aSChris Wilson select KCMP 14405cb366bbSAdrian Reber default n 14415cb366bbSAdrian Reber help 14425cb366bbSAdrian Reber Enables additional kernel features in a sake of checkpoint/restore. 14435cb366bbSAdrian Reber In particular it adds auxiliary prctl codes to setup process text, 14445cb366bbSAdrian Reber data and heap segment sizes, and a few additional /proc filesystem 14455cb366bbSAdrian Reber entries. 14465cb366bbSAdrian Reber 14475cb366bbSAdrian Reber If unsure, say N here. 14485cb366bbSAdrian Reber 14495091faa4SMike Galbraithconfig SCHED_AUTOGROUP 14505091faa4SMike Galbraith bool "Automatic process group scheduling" 14515091faa4SMike Galbraith select CGROUPS 14525091faa4SMike Galbraith select CGROUP_SCHED 14535091faa4SMike Galbraith select FAIR_GROUP_SCHED 14545091faa4SMike Galbraith help 14555091faa4SMike Galbraith This option optimizes the scheduler for common desktop workloads by 14565091faa4SMike Galbraith automatically creating and populating task groups. This separation 14575091faa4SMike Galbraith of workloads isolates aggressive CPU burners (like build jobs) from 14585091faa4SMike Galbraith desktop applications. Task group autogeneration is currently based 14595091faa4SMike Galbraith upon task session. 14605091faa4SMike Galbraith 14617af37becSDaniel Lezcanoconfig RELAY 14627af37becSDaniel Lezcano bool "Kernel->user space relay support (formerly relayfs)" 146326b5679eSPeter Zijlstra select IRQ_WORK 14647af37becSDaniel Lezcano help 14657af37becSDaniel Lezcano This option enables support for relay interface support in 14667af37becSDaniel Lezcano certain file systems (such as debugfs). 14677af37becSDaniel Lezcano It is designed to provide an efficient mechanism for tools and 14687af37becSDaniel Lezcano facilities to relay large amounts of data from kernel space to 14697af37becSDaniel Lezcano user space. 14707af37becSDaniel Lezcano 14717af37becSDaniel Lezcano If unsure, say N. 14727af37becSDaniel Lezcano 1473f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 1474f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1475f991633dSDimitri Gorokhovik help 1476f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 1477f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 1478f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 1479f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 14808c27ceffSMauro Carvalho Chehab etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1481f991633dSDimitri Gorokhovik 1482f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 1483f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 1484f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 1485f991633dSDimitri Gorokhovik 1486f991633dSDimitri Gorokhovik If unsure say Y. 1487f991633dSDimitri Gorokhovik 1488c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 1489c33df4eaSJean-Paul Saman 1490dbec4866SSam Ravnborgsource "usr/Kconfig" 1491dbec4866SSam Ravnborg 1492c33df4eaSJean-Paul Samanendif 1493c33df4eaSJean-Paul Saman 149476db5a27SMasami Hiramatsuconfig BOOT_CONFIG 149576db5a27SMasami Hiramatsu bool "Boot config support" 1496a2a9d67aSMasami Hiramatsu select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 149776db5a27SMasami Hiramatsu help 149876db5a27SMasami Hiramatsu Extra boot config allows system admin to pass a config file as 149976db5a27SMasami Hiramatsu complemental extension of kernel cmdline when booting. 15000947db01SMasami Hiramatsu The boot config file must be attached at the end of initramfs 150185c46b78SMasami Hiramatsu with checksum, size and magic word. 15020947db01SMasami Hiramatsu See <file:Documentation/admin-guide/bootconfig.rst> for details. 150376db5a27SMasami Hiramatsu 150476db5a27SMasami Hiramatsu If unsure, say Y. 150576db5a27SMasami Hiramatsu 1506b743852cSPaul E. McKenneyconfig BOOT_CONFIG_FORCE 1507b743852cSPaul E. McKenney bool "Force unconditional bootconfig processing" 1508b743852cSPaul E. McKenney depends on BOOT_CONFIG 15096ded8a28SPaul E. McKenney default y if BOOT_CONFIG_EMBED 1510b743852cSPaul E. McKenney help 1511b743852cSPaul E. McKenney With this Kconfig option set, BOOT_CONFIG processing is carried 1512b743852cSPaul E. McKenney out even when the "bootconfig" kernel-boot parameter is omitted. 1513b743852cSPaul E. McKenney In fact, with this Kconfig option set, there is no way to 1514b743852cSPaul E. McKenney make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1515b743852cSPaul E. McKenney parameters. 1516b743852cSPaul E. McKenney 1517b743852cSPaul E. McKenney If unsure, say N. 1518b743852cSPaul E. McKenney 1519a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED 1520a2a9d67aSMasami Hiramatsu bool "Embed bootconfig file in the kernel" 1521a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG 1522a2a9d67aSMasami Hiramatsu help 1523a2a9d67aSMasami Hiramatsu Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1524a2a9d67aSMasami Hiramatsu kernel. Usually, the bootconfig file is loaded with the initrd 1525a2a9d67aSMasami Hiramatsu image. But if the system doesn't support initrd, this option will 1526a2a9d67aSMasami Hiramatsu help you by embedding a bootconfig file while building the kernel. 1527a2a9d67aSMasami Hiramatsu 1528a2a9d67aSMasami Hiramatsu If unsure, say N. 1529a2a9d67aSMasami Hiramatsu 1530a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED_FILE 1531a2a9d67aSMasami Hiramatsu string "Embedded bootconfig file path" 1532a2a9d67aSMasami Hiramatsu depends on BOOT_CONFIG_EMBED 1533a2a9d67aSMasami Hiramatsu help 1534a2a9d67aSMasami Hiramatsu Specify a bootconfig file which will be embedded to the kernel. 1535a2a9d67aSMasami Hiramatsu This bootconfig will be used if there is no initrd or no other 1536a2a9d67aSMasami Hiramatsu bootconfig in the initrd. 1537a2a9d67aSMasami Hiramatsu 1538032a7302SDouglas Andersonconfig CMDLINE_LOG_WRAP_IDEAL_LEN 1539032a7302SDouglas Anderson int "Length to try to wrap the cmdline when logged at boot" 1540032a7302SDouglas Anderson default 1021 1541032a7302SDouglas Anderson range 0 1021 1542032a7302SDouglas Anderson help 1543032a7302SDouglas Anderson At boot time, the kernel command line is logged to the console. 1544032a7302SDouglas Anderson The log message will start with the prefix "Kernel command line: ". 1545032a7302SDouglas Anderson The log message will attempt to be wrapped (split into multiple log 1546032a7302SDouglas Anderson messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1547032a7302SDouglas Anderson If wrapping happens, each log message will start with the prefix and 1548032a7302SDouglas Anderson all but the last message will end with " \". Messages may exceed the 1549032a7302SDouglas Anderson ideal length if a place to wrap isn't found before the specified 1550032a7302SDouglas Anderson number of characters. 1551032a7302SDouglas Anderson 1552032a7302SDouglas Anderson A value of 0 disables wrapping, though be warned that the maximum 1553032a7302SDouglas Anderson length of a log message (1021 characters) may cause the cmdline to 1554032a7302SDouglas Anderson be truncated. 1555032a7302SDouglas Anderson 15561274aea1SDavid Disseldorpconfig INITRAMFS_PRESERVE_MTIME 15571274aea1SDavid Disseldorp bool "Preserve cpio archive mtimes in initramfs" 155874792608SGeert Uytterhoeven depends on BLK_DEV_INITRD 15591274aea1SDavid Disseldorp default y 15601274aea1SDavid Disseldorp help 15611274aea1SDavid Disseldorp Each entry in an initramfs cpio archive carries an mtime value. When 15621274aea1SDavid Disseldorp enabled, extracted cpio items take this mtime, with directory mtime 15631274aea1SDavid Disseldorp setting deferred until after creation of any child entries. 15641274aea1SDavid Disseldorp 15651274aea1SDavid Disseldorp If unsure, say Y. 15661274aea1SDavid Disseldorp 156783c0b272SDavid Disseldorpconfig INITRAMFS_TEST 156883c0b272SDavid Disseldorp bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 156983c0b272SDavid Disseldorp depends on BLK_DEV_INITRD && KUNIT=y 157083c0b272SDavid Disseldorp default KUNIT_ALL_TESTS 157183c0b272SDavid Disseldorp help 157283c0b272SDavid Disseldorp Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 157383c0b272SDavid Disseldorp 1574877417e6SArnd Bergmannchoice 1575877417e6SArnd Bergmann prompt "Compiler optimization level" 15762cc3ce24SUlf Magnusson default CC_OPTIMIZE_FOR_PERFORMANCE 1577877417e6SArnd Bergmann 1578877417e6SArnd Bergmannconfig CC_OPTIMIZE_FOR_PERFORMANCE 157915f5db60SMasahiro Yamada bool "Optimize for performance (-O2)" 1580877417e6SArnd Bergmann help 1581877417e6SArnd Bergmann This is the default optimization level for the kernel, building 1582877417e6SArnd Bergmann with the "-O2" compiler flag for best performance and most 1583877417e6SArnd Bergmann helpful compile-time warnings. 1584877417e6SArnd Bergmann 1585c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 158615f5db60SMasahiro Yamada bool "Optimize for size (-Os)" 1587c45b4f1fSLinus Torvalds help 1588ce3b487fSMasahiro Yamada Choosing this option will pass "-Os" to your compiler resulting 1589ce3b487fSMasahiro Yamada in a smaller kernel. 1590c45b4f1fSLinus Torvalds 1591877417e6SArnd Bergmannendchoice 1592877417e6SArnd Bergmann 15935d20ee31SNicholas Pigginconfig HAVE_LD_DEAD_CODE_DATA_ELIMINATION 15945d20ee31SNicholas Piggin bool 15955d20ee31SNicholas Piggin help 15965d20ee31SNicholas Piggin This requires that the arch annotates or otherwise protects 15975d20ee31SNicholas Piggin its external entry points from being discarded. Linker scripts 15985d20ee31SNicholas Piggin must also merge .text.*, .data.*, and .bss.* correctly into 15995d20ee31SNicholas Piggin output sections. Care must be taken not to pull in unrelated 16005d20ee31SNicholas Piggin sections (e.g., '.text.init'). Typically '.' in section names 16015d20ee31SNicholas Piggin is used to distinguish them from label names / C identifiers. 16025d20ee31SNicholas Piggin 16035d20ee31SNicholas Pigginconfig LD_DEAD_CODE_DATA_ELIMINATION 16045d20ee31SNicholas Piggin bool "Dead code and data elimination (EXPERIMENTAL)" 16055d20ee31SNicholas Piggin depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 16065d20ee31SNicholas Piggin depends on EXPERT 1607e85d1d65SMasahiro Yamada depends on $(cc-option,-ffunction-sections -fdata-sections) 1608e85d1d65SMasahiro Yamada depends on $(ld-option,--gc-sections) 16095d20ee31SNicholas Piggin help 16108b9d2712SMasahiro Yamada Enable this if you want to do dead code and data elimination with 16118b9d2712SMasahiro Yamada the linker by compiling with -ffunction-sections -fdata-sections, 16128b9d2712SMasahiro Yamada and linking with --gc-sections. 16135d20ee31SNicholas Piggin 16145d20ee31SNicholas Piggin This can reduce on disk and in-memory size of the kernel 16155d20ee31SNicholas Piggin code and static data, particularly for small configs and 16165d20ee31SNicholas Piggin on small systems. This has the possibility of introducing 16175d20ee31SNicholas Piggin silently broken kernel if the required annotations are not 16185d20ee31SNicholas Piggin present. This option is not well tested yet, so use at your 16195d20ee31SNicholas Piggin own risk. 16205d20ee31SNicholas Piggin 162159612b24SNathan Chancellorconfig LD_ORPHAN_WARN 162259612b24SNathan Chancellor def_bool y 162359612b24SNathan Chancellor depends on ARCH_WANT_LD_ORPHAN_WARN 162459612b24SNathan Chancellor depends on $(ld-option,--orphan-handling=warn) 1625e1789d7cSXin Li depends on $(ld-option,--orphan-handling=error) 1626e1789d7cSXin Li 1627e1789d7cSXin Liconfig LD_ORPHAN_WARN_LEVEL 1628e1789d7cSXin Li string 1629e1789d7cSXin Li depends on LD_ORPHAN_WARN 1630e1789d7cSXin Li default "error" if WERROR 1631e1789d7cSXin Li default "warn" 163259612b24SNathan Chancellor 16330847062aSRandy Dunlapconfig SYSCTL 16340847062aSRandy Dunlap bool 16350847062aSRandy Dunlap 1636657a5209SMike Frysingerconfig HAVE_UID16 1637657a5209SMike Frysinger bool 1638657a5209SMike Frysinger 1639657a5209SMike Frysingerconfig SYSCTL_EXCEPTION_TRACE 1640657a5209SMike Frysinger bool 1641657a5209SMike Frysinger help 1642657a5209SMike Frysinger Enable support for /proc/sys/debug/exception-trace. 1643657a5209SMike Frysinger 1644657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_NO_WARN 1645657a5209SMike Frysinger bool 1646657a5209SMike Frysinger help 1647657a5209SMike Frysinger Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1648657a5209SMike Frysinger Allows arch to define/use @no_unaligned_warning to possibly warn 1649657a5209SMike Frysinger about unaligned access emulation going on under the hood. 1650657a5209SMike Frysinger 1651657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_ALLOW 1652657a5209SMike Frysinger bool 1653657a5209SMike Frysinger help 1654657a5209SMike Frysinger Enable support for /proc/sys/kernel/unaligned-trap 1655657a5209SMike Frysinger Allows arches to define/use @unaligned_enabled to runtime toggle 1656657a5209SMike Frysinger the unaligned access emulation. 1657657a5209SMike Frysinger see arch/parisc/kernel/unaligned.c for reference 1658657a5209SMike Frysinger 1659c443279aSChristian Braunerconfig SYSFS_SYSCALL 1660c443279aSChristian Brauner bool "Sysfs syscall support" 1661c443279aSChristian Brauner default n 1662c443279aSChristian Brauner help 1663c443279aSChristian Brauner sys_sysfs is an obsolete system call no longer supported in libc. 1664c443279aSChristian Brauner Note that disabling this option is more secure but might break 1665c443279aSChristian Brauner compatibility with some systems. 1666c443279aSChristian Brauner 1667c443279aSChristian Brauner If unsure say N here. 1668c443279aSChristian Brauner 1669657a5209SMike Frysingerconfig HAVE_PCSPKR_PLATFORM 1670657a5209SMike Frysinger bool 1671657a5209SMike Frysinger 16726a108a14SDavid Rientjesmenuconfig EXPERT 16736a108a14SDavid Rientjes bool "Configure standard kernel features (expert users)" 1674f505c553SJosh Triplett # Unhide debug options, to make the on-by-default options visible 1675f505c553SJosh Triplett select DEBUG_KERNEL 16761da177e4SLinus Torvalds help 16771da177e4SLinus Torvalds This option allows certain base kernel options and settings 16781da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 16791da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 16801da177e4SLinus Torvalds Only use this if you really know what you are doing. 16811da177e4SLinus Torvalds 1682ae81f9e3SChuck Ebbertconfig UID16 16836a108a14SDavid Rientjes bool "Enable 16-bit UID system calls" if EXPERT 16842813893fSIulia Manda depends on HAVE_UID16 && MULTIUSER 1685ae81f9e3SChuck Ebbert default y 1686ae81f9e3SChuck Ebbert help 1687ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 1688ae81f9e3SChuck Ebbert 16892813893fSIulia Mandaconfig MULTIUSER 16902813893fSIulia Manda bool "Multiple users, groups and capabilities support" if EXPERT 16912813893fSIulia Manda default y 16922813893fSIulia Manda help 16932813893fSIulia Manda This option enables support for non-root users, groups and 16942813893fSIulia Manda capabilities. 16952813893fSIulia Manda 16962813893fSIulia Manda If you say N here, all processes will run with UID 0, GID 0, and all 16972813893fSIulia Manda possible capabilities. Saying N here also compiles out support for 16982813893fSIulia Manda system calls related to UIDs, GIDs, and capabilities, such as setuid, 16992813893fSIulia Manda setgid, and capset. 17002813893fSIulia Manda 17012813893fSIulia Manda If unsure, say Y here. 17022813893fSIulia Manda 1703f6187769SFabian Frederickconfig SGETMASK_SYSCALL 1704f6187769SFabian Frederick bool "sgetmask/ssetmask syscalls support" if EXPERT 1705cd14b018SMasahiro Yamada default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1706a7f7f624SMasahiro Yamada help 1707f6187769SFabian Frederick sys_sgetmask and sys_ssetmask are obsolete system calls 1708f6187769SFabian Frederick no longer supported in libc but still enabled by default in some 1709f6187769SFabian Frederick architectures. 1710f6187769SFabian Frederick 1711f6187769SFabian Frederick If unsure, leave the default option here. 1712f6187769SFabian Frederick 1713d1b069f5SRandy Dunlapconfig FHANDLE 1714d1b069f5SRandy Dunlap bool "open by fhandle syscalls" if EXPERT 1715d1b069f5SRandy Dunlap select EXPORTFS 1716d1b069f5SRandy Dunlap default y 1717d1b069f5SRandy Dunlap help 1718d1b069f5SRandy Dunlap If you say Y here, a user level program will be able to map 1719d1b069f5SRandy Dunlap file names to handle and then later use the handle for 1720d1b069f5SRandy Dunlap different file system operations. This is useful in implementing 1721d1b069f5SRandy Dunlap userspace file servers, which now track files using handles instead 1722d1b069f5SRandy Dunlap of names. The handle would remain the same even if file names 1723d1b069f5SRandy Dunlap get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1724d1b069f5SRandy Dunlap syscalls. 1725d1b069f5SRandy Dunlap 1726baa73d9eSNicolas Pitreconfig POSIX_TIMERS 1727baa73d9eSNicolas Pitre bool "Posix Clocks & timers" if EXPERT 1728baa73d9eSNicolas Pitre default y 1729baa73d9eSNicolas Pitre help 1730baa73d9eSNicolas Pitre This includes native support for POSIX timers to the kernel. 1731baa73d9eSNicolas Pitre Some embedded systems have no use for them and therefore they 1732baa73d9eSNicolas Pitre can be configured out to reduce the size of the kernel image. 1733baa73d9eSNicolas Pitre 1734baa73d9eSNicolas Pitre When this option is disabled, the following syscalls won't be 1735baa73d9eSNicolas Pitre available: timer_create, timer_gettime: timer_getoverrun, 1736baa73d9eSNicolas Pitre timer_settime, timer_delete, clock_adjtime, getitimer, 1737baa73d9eSNicolas Pitre setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1738baa73d9eSNicolas Pitre clock_getres and clock_nanosleep syscalls will be limited to 1739baa73d9eSNicolas Pitre CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1740baa73d9eSNicolas Pitre 1741baa73d9eSNicolas Pitre If unsure say y. 1742baa73d9eSNicolas Pitre 1743d59745ceSMatt Mackallconfig PRINTK 1744d59745ceSMatt Mackall default y 17456a108a14SDavid Rientjes bool "Enable support for printk" if EXPERT 174674876a98SFrederic Weisbecker select IRQ_WORK 1747d59745ceSMatt Mackall help 1748d59745ceSMatt Mackall This option enables normal printk support. Removing it 1749d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 1750d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 1751d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 1752d59745ceSMatt Mackall strongly discouraged. 1753d59745ceSMatt Mackall 17545ea2bcdfSThomas Weißschuhconfig PRINTK_RINGBUFFER_KUNIT_TEST 17555ea2bcdfSThomas Weißschuh tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 17565ea2bcdfSThomas Weißschuh depends on PRINTK && KUNIT 17575ea2bcdfSThomas Weißschuh default KUNIT_ALL_TESTS 17585ea2bcdfSThomas Weißschuh help 17595ea2bcdfSThomas Weißschuh This builds the printk ringbuffer KUnit test suite. 17605ea2bcdfSThomas Weißschuh 17615ea2bcdfSThomas Weißschuh For more information on KUnit and unit tests in general, please refer 17625ea2bcdfSThomas Weißschuh to the KUnit documentation. 17635ea2bcdfSThomas Weißschuh 17645ea2bcdfSThomas Weißschuh If unsure, say N. 17655ea2bcdfSThomas Weißschuh 1766c8538a7aSMatt Mackallconfig BUG 17676a108a14SDavid Rientjes bool "BUG() support" if EXPERT 1768c8538a7aSMatt Mackall default y 1769c8538a7aSMatt Mackall help 1770c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 1771c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 1772c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 1773c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 1774c8538a7aSMatt Mackall Just say Y. 1775c8538a7aSMatt Mackall 1776708e9a79SMatt Mackallconfig ELF_CORE 1777046d662fSAlex Kelly depends on COREDUMP 1778708e9a79SMatt Mackall default y 17796a108a14SDavid Rientjes bool "Enable ELF core dumps" if EXPERT 1780708e9a79SMatt Mackall help 1781708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 1782708e9a79SMatt Mackall 17838761f1abSRalf Baechle 1784e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 17856a108a14SDavid Rientjes bool "Enable PC-Speaker support" if EXPERT 17868761f1abSRalf Baechle depends on HAVE_PCSPKR_PLATFORM 178715f304b6SRalf Baechle select I8253_LOCK 1788e5e1d3cbSStas Sergeev default y 1789e5e1d3cbSStas Sergeev help 1790e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 1791e5e1d3cbSStas Sergeev support, saving some memory. 1792e5e1d3cbSStas Sergeev 179327021649SYoann Congalconfig BASE_SMALL 179427021649SYoann Congal bool "Enable smaller-sized data structures for core" if EXPERT 17951da177e4SLinus Torvalds help 179627021649SYoann Congal Enabling this option reduces the size of miscellaneous core 17971da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 17981da177e4SLinus Torvalds but may reduce performance. 17991da177e4SLinus Torvalds 18001da177e4SLinus Torvaldsconfig FUTEX 18016a108a14SDavid Rientjes bool "Enable futex support" if EXPERT 18023f2bedabSArnd Bergmann depends on !(SPARC32 && SMP) 18031da177e4SLinus Torvalds default y 1804bc2eecd7SNicolas Pitre imply RT_MUTEXES 18051da177e4SLinus Torvalds help 18061da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18071da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 18081da177e4SLinus Torvalds run glibc-based applications correctly. 18091da177e4SLinus Torvalds 1810bc2eecd7SNicolas Pitreconfig FUTEX_PI 1811bc2eecd7SNicolas Pitre bool 1812bc2eecd7SNicolas Pitre depends on FUTEX && RT_MUTEXES 1813bc2eecd7SNicolas Pitre default y 1814bc2eecd7SNicolas Pitre 181580367ad0SSebastian Andrzej Siewiorconfig FUTEX_PRIVATE_HASH 181680367ad0SSebastian Andrzej Siewior bool 181780367ad0SSebastian Andrzej Siewior depends on FUTEX && !BASE_SMALL && MMU 181880367ad0SSebastian Andrzej Siewior default y 181980367ad0SSebastian Andrzej Siewior 1820c042c505SPeter Zijlstraconfig FUTEX_MPOL 1821c042c505SPeter Zijlstra bool 1822c042c505SPeter Zijlstra depends on FUTEX && NUMA 1823c042c505SPeter Zijlstra default y 1824c042c505SPeter Zijlstra 18251da177e4SLinus Torvaldsconfig EPOLL 18266a108a14SDavid Rientjes bool "Enable eventpoll support" if EXPERT 18271da177e4SLinus Torvalds default y 18281da177e4SLinus Torvalds help 18291da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 18301da177e4SLinus Torvalds support for epoll family of system calls. 18311da177e4SLinus Torvalds 1832fba2afaaSDavide Libenziconfig SIGNALFD 18336a108a14SDavid Rientjes bool "Enable signalfd() system call" if EXPERT 1834fba2afaaSDavide Libenzi default y 1835fba2afaaSDavide Libenzi help 1836fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 1837fba2afaaSDavide Libenzi on a file descriptor. 1838fba2afaaSDavide Libenzi 1839fba2afaaSDavide Libenzi If unsure, say Y. 1840fba2afaaSDavide Libenzi 1841b215e283SDavide Libenziconfig TIMERFD 18426a108a14SDavid Rientjes bool "Enable timerfd() system call" if EXPERT 1843b215e283SDavide Libenzi default y 1844b215e283SDavide Libenzi help 1845b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 1846b215e283SDavide Libenzi events on a file descriptor. 1847b215e283SDavide Libenzi 1848b215e283SDavide Libenzi If unsure, say Y. 1849b215e283SDavide Libenzi 1850e1ad7468SDavide Libenziconfig EVENTFD 18516a108a14SDavid Rientjes bool "Enable eventfd() system call" if EXPERT 1852e1ad7468SDavide Libenzi default y 1853e1ad7468SDavide Libenzi help 1854e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 1855e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 1856e1ad7468SDavide Libenzi 1857e1ad7468SDavide Libenzi If unsure, say Y. 1858e1ad7468SDavide Libenzi 18591da177e4SLinus Torvaldsconfig SHMEM 18606a108a14SDavid Rientjes bool "Use full shmem filesystem" if EXPERT 18611da177e4SLinus Torvalds default y 18621da177e4SLinus Torvalds depends on MMU 18631da177e4SLinus Torvalds help 18641da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 18651da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 18661da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 18671da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 18681da177e4SLinus Torvalds which may be appropriate on small systems without swap. 18691da177e4SLinus Torvalds 1870ebf3f09cSThomas Petazzoniconfig AIO 18716a108a14SDavid Rientjes bool "Enable AIO support" if EXPERT 1872ebf3f09cSThomas Petazzoni default y 1873ebf3f09cSThomas Petazzoni help 1874ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 1875ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 1876ebf3f09cSThomas Petazzoni this option saves about 7k. 1877ebf3f09cSThomas Petazzoni 18782b188cc1SJens Axboeconfig IO_URING 18792b188cc1SJens Axboe bool "Enable IO uring support" if EXPERT 1880561fb04aSJens Axboe select IO_WQ 18812b188cc1SJens Axboe default y 18822b188cc1SJens Axboe help 18832b188cc1SJens Axboe This option enables support for the io_uring interface, enabling 18842b188cc1SJens Axboe applications to submit and complete IO through submission and 18852b188cc1SJens Axboe completion rings that are shared between the kernel and application. 18862b188cc1SJens Axboe 18871802656eSJens Axboeconfig GCOV_PROFILE_URING 18881802656eSJens Axboe bool "Enable GCOV profiling on the io_uring subsystem" 1889d1fbe1ebSRandy Dunlap depends on IO_URING && GCOV_KERNEL 18901802656eSJens Axboe help 18911802656eSJens Axboe Enable GCOV profiling on the io_uring subsystem, to facilitate 18921802656eSJens Axboe code coverage testing. 18931802656eSJens Axboe 18941802656eSJens Axboe If unsure, say N. 18951802656eSJens Axboe 18961802656eSJens Axboe Note that this will have a negative impact on the performance of 18971802656eSJens Axboe the io_uring subsystem, hence this should only be enabled for 18981802656eSJens Axboe specific test purposes. 18991802656eSJens Axboe 19003a0ae385SPavel Begunkovconfig IO_URING_MOCK_FILE 19013a0ae385SPavel Begunkov tristate "Enable io_uring mock files (Experimental)" if EXPERT 19023a0ae385SPavel Begunkov default n 19033a0ae385SPavel Begunkov depends on IO_URING 19043a0ae385SPavel Begunkov help 1905*9e7dc228SJ. Neuschäfer Enable mock files for io_uring subsystem testing. The ABI might 19063a0ae385SPavel Begunkov still change, so it's still experimental and should only be enabled 19073a0ae385SPavel Begunkov for specific test purposes. 19083a0ae385SPavel Begunkov 19093a0ae385SPavel Begunkov If unsure, say N. 19103a0ae385SPavel Begunkov 1911d3ac21caSJosh Triplettconfig ADVISE_SYSCALLS 1912d3ac21caSJosh Triplett bool "Enable madvise/fadvise syscalls" if EXPERT 1913d3ac21caSJosh Triplett default y 1914d3ac21caSJosh Triplett help 1915d3ac21caSJosh Triplett This option enables the madvise and fadvise syscalls, used by 1916d3ac21caSJosh Triplett applications to advise the kernel about their future memory or file 1917d3ac21caSJosh Triplett usage, improving performance. If building an embedded system where no 1918d3ac21caSJosh Triplett applications use these syscalls, you can disable this option to save 1919d3ac21caSJosh Triplett space. 1920d3ac21caSJosh Triplett 19215b25b13aSMathieu Desnoyersconfig MEMBARRIER 19225b25b13aSMathieu Desnoyers bool "Enable membarrier() system call" if EXPERT 19235b25b13aSMathieu Desnoyers default y 19245b25b13aSMathieu Desnoyers help 19255b25b13aSMathieu Desnoyers Enable the membarrier() system call that allows issuing memory 19265b25b13aSMathieu Desnoyers barriers across all running threads, which can be used to distribute 19275b25b13aSMathieu Desnoyers the cost of user-space memory barriers asymmetrically by transforming 19285b25b13aSMathieu Desnoyers pairs of memory barriers into pairs consisting of membarrier() and a 19295b25b13aSMathieu Desnoyers compiler barrier. 19305b25b13aSMathieu Desnoyers 19315b25b13aSMathieu Desnoyers If unsure, say Y. 19325b25b13aSMathieu Desnoyers 1933a751ea34SRandy Dunlapconfig KCMP 1934a751ea34SRandy Dunlap bool "Enable kcmp() system call" if EXPERT 1935a751ea34SRandy Dunlap help 1936a751ea34SRandy Dunlap Enable the kernel resource comparison system call. It provides 1937a751ea34SRandy Dunlap user-space with the ability to compare two processes to see if they 1938a751ea34SRandy Dunlap share a common resource, such as a file descriptor or even virtual 1939a751ea34SRandy Dunlap memory space. 1940a751ea34SRandy Dunlap 1941a751ea34SRandy Dunlap If unsure, say N. 1942a751ea34SRandy Dunlap 1943a751ea34SRandy Dunlapconfig RSEQ 1944a751ea34SRandy Dunlap bool "Enable rseq() system call" if EXPERT 1945a751ea34SRandy Dunlap default y 1946a751ea34SRandy Dunlap depends on HAVE_RSEQ 1947a751ea34SRandy Dunlap select MEMBARRIER 1948a751ea34SRandy Dunlap help 1949a751ea34SRandy Dunlap Enable the restartable sequences system call. It provides a 1950a751ea34SRandy Dunlap user-space cache for the current CPU number value, which 1951a751ea34SRandy Dunlap speeds up getting the current CPU number from user-space, 1952a751ea34SRandy Dunlap as well as an ABI to speed up user-space operations on 1953a751ea34SRandy Dunlap per-CPU data. 1954a751ea34SRandy Dunlap 1955a751ea34SRandy Dunlap If unsure, say Y. 1956a751ea34SRandy Dunlap 1957d7a5da7aSThomas Gleixnerconfig RSEQ_SLICE_EXTENSION 1958d7a5da7aSThomas Gleixner bool "Enable rseq-based time slice extension mechanism" 1959d7a5da7aSThomas Gleixner depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 1960d7a5da7aSThomas Gleixner help 1961d7a5da7aSThomas Gleixner Allows userspace to request a limited time slice extension when 1962d7a5da7aSThomas Gleixner returning from an interrupt to user space via the RSEQ shared 1963d7a5da7aSThomas Gleixner data ABI. If granted, that allows to complete a critical section, 1964d7a5da7aSThomas Gleixner so that other threads are not stuck on a conflicted resource, 1965d7a5da7aSThomas Gleixner while the task is scheduled out. 1966d7a5da7aSThomas Gleixner 1967d7a5da7aSThomas Gleixner If unsure, say N. 1968d7a5da7aSThomas Gleixner 196954129104SThomas Gleixnerconfig RSEQ_STATS 197054129104SThomas Gleixner default n 197154129104SThomas Gleixner bool "Enable lightweight statistics of restartable sequences" if EXPERT 197254129104SThomas Gleixner depends on RSEQ && DEBUG_FS 197354129104SThomas Gleixner help 197454129104SThomas Gleixner Enable lightweight counters which expose information about the 197554129104SThomas Gleixner frequency of RSEQ operations via debugfs. Mostly interesting for 197654129104SThomas Gleixner kernel debugging or performance analysis. While lightweight it's 197754129104SThomas Gleixner still adding code into the user/kernel mode transitions. 197854129104SThomas Gleixner 197954129104SThomas Gleixner If unsure, say N. 198054129104SThomas Gleixner 19819c37cb6eSThomas Gleixnerconfig RSEQ_DEBUG_DEFAULT_ENABLE 19829c37cb6eSThomas Gleixner default n 19839c37cb6eSThomas Gleixner bool "Enable restartable sequences debug mode by default" if EXPERT 19849c37cb6eSThomas Gleixner depends on RSEQ 19859c37cb6eSThomas Gleixner help 19869c37cb6eSThomas Gleixner This enables the static branch for debug mode of restartable 19879c37cb6eSThomas Gleixner sequences. 19889c37cb6eSThomas Gleixner 19899c37cb6eSThomas Gleixner This also can be controlled on the kernel command line via the 19909c37cb6eSThomas Gleixner command line parameter "rseq_debug=0/1" and through debugfs. 19919c37cb6eSThomas Gleixner 19929c37cb6eSThomas Gleixner If unsure, say N. 19939c37cb6eSThomas Gleixner 1994a751ea34SRandy Dunlapconfig DEBUG_RSEQ 1995a751ea34SRandy Dunlap default n 1996a751ea34SRandy Dunlap bool "Enable debugging of rseq() system call" if EXPERT 19973db6b38dSThomas Gleixner depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 19989c37cb6eSThomas Gleixner select RSEQ_DEBUG_DEFAULT_ENABLE 1999a751ea34SRandy Dunlap help 2000a751ea34SRandy Dunlap Enable extra debugging checks for the rseq system call. 2001a751ea34SRandy Dunlap 2002a751ea34SRandy Dunlap If unsure, say N. 2003a751ea34SRandy Dunlap 2004a751ea34SRandy Dunlapconfig CACHESTAT_SYSCALL 2005a751ea34SRandy Dunlap bool "Enable cachestat() system call" if EXPERT 2006a751ea34SRandy Dunlap default y 2007a751ea34SRandy Dunlap help 2008a751ea34SRandy Dunlap Enable the cachestat system call, which queries the page cache 2009a751ea34SRandy Dunlap statistics of a file (number of cached pages, dirty pages, 2010a751ea34SRandy Dunlap pages marked for writeback, (recently) evicted pages). 2011a751ea34SRandy Dunlap 2012a751ea34SRandy Dunlap If unsure say Y here. 2013a751ea34SRandy Dunlap 2014d1b069f5SRandy Dunlapconfig KALLSYMS 2015d1b069f5SRandy Dunlap bool "Load all symbols for debugging/ksymoops" if EXPERT 2016d1b069f5SRandy Dunlap default y 2017d1b069f5SRandy Dunlap help 2018d1b069f5SRandy Dunlap Say Y here to let the kernel print out symbolic crash information and 2019d1b069f5SRandy Dunlap symbolic stack backtraces. This increases the size of the kernel 2020d1b069f5SRandy Dunlap somewhat, as all symbols have to be loaded into the kernel image. 2021d1b069f5SRandy Dunlap 202230f3bb09SZhen Leiconfig KALLSYMS_SELFTEST 202330f3bb09SZhen Lei bool "Test the basic functions and performance of kallsyms" 202430f3bb09SZhen Lei depends on KALLSYMS 202530f3bb09SZhen Lei default n 202630f3bb09SZhen Lei help 202730f3bb09SZhen Lei Test the basic functions and performance of some interfaces, such as 202830f3bb09SZhen Lei kallsyms_lookup_name. It also calculates the compression rate of the 202930f3bb09SZhen Lei kallsyms compression algorithm for the current symbol set. 203030f3bb09SZhen Lei 203130f3bb09SZhen Lei Start self-test automatically after system startup. Suggest executing 203230f3bb09SZhen Lei "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 203330f3bb09SZhen Lei displayed in the last line, indicating that the test is complete. 203430f3bb09SZhen Lei 2035d1b069f5SRandy Dunlapconfig KALLSYMS_ALL 2036d1b069f5SRandy Dunlap bool "Include all symbols in kallsyms" 2037d1b069f5SRandy Dunlap depends on DEBUG_KERNEL && KALLSYMS 2038d1b069f5SRandy Dunlap help 2039d1b069f5SRandy Dunlap Normally kallsyms only contains the symbols of functions for nicer 2040d1b069f5SRandy Dunlap OOPS messages and backtraces (i.e., symbols from the text and inittext 2041bdf0fe33SBaruch Siach sections). This is sufficient for most cases. And only if you want to 2042bdf0fe33SBaruch Siach enable kernel live patching, or other less common use cases (e.g., 2043bdf0fe33SBaruch Siach when a debugger is used) all symbols are required (i.e., names of 2044bdf0fe33SBaruch Siach variables from the data sections, etc). 2045d1b069f5SRandy Dunlap 2046d1b069f5SRandy Dunlap This option makes sure that all symbols are loaded into the kernel 2047d1b069f5SRandy Dunlap image (i.e., symbols from all sections) in cost of increased kernel 2048d1b069f5SRandy Dunlap size (depending on the kernel configuration, it may be 300KiB or 2049d1b069f5SRandy Dunlap something like this). 2050d1b069f5SRandy Dunlap 2051bdf0fe33SBaruch Siach Say N unless you really need all symbols, or kernel live patching. 2052d1b069f5SRandy Dunlap 2053d1b069f5SRandy Dunlap# end of the "standard kernel features (expert users)" menu 2054d1b069f5SRandy Dunlap 20553ccfebedSMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_CALLBACKS 20563ccfebedSMathieu Desnoyers bool 20573ccfebedSMathieu Desnoyers 205870216e18SMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_SYNC_CORE 205970216e18SMathieu Desnoyers bool 206070216e18SMathieu Desnoyers 20615796d396SJeff Xuconfig ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 20625796d396SJeff Xu bool 20635796d396SJeff Xu help 20645796d396SJeff Xu Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 20655796d396SJeff Xu 20665796d396SJeff Xu A 64-bit kernel is required for the memory sealing feature. 20675796d396SJeff Xu No specific hardware features from the CPU are needed. 20685796d396SJeff Xu 20695796d396SJeff Xu To enable this feature, the architecture needs to update their 20705796d396SJeff Xu special mappings calls to include the sealing flag and confirm 20715796d396SJeff Xu that it doesn't unmap/remap system mappings during the life 20725796d396SJeff Xu time of the process. The existence of this flag for an architecture 20735796d396SJeff Xu implies that it does not require the remapping of the system 20745796d396SJeff Xu mappings during process lifetime, so sealing these mappings is safe 20755796d396SJeff Xu from a kernel perspective. 20765796d396SJeff Xu 20775796d396SJeff Xu After the architecture enables this, a distribution can set 20785796d396SJeff Xu CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 20795796d396SJeff Xu 20805796d396SJeff Xu For complete descriptions of memory sealing, please see 20815796d396SJeff Xu Documentation/userspace-api/mseal.rst 20825796d396SJeff Xu 2083cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS 20840793a61dSThomas Gleixner bool 2085018df72dSMike Frysinger help 2086018df72dSMike Frysinger See tools/perf/design.txt for details. 20870793a61dSThomas Gleixner 20882aef6f30SSean Christophersonconfig GUEST_PERF_EVENTS 20892aef6f30SSean Christopherson bool 20902aef6f30SSean Christopherson depends on HAVE_PERF_EVENTS 20912aef6f30SSean Christopherson 2092eff95e17SKan Liangconfig PERF_GUEST_MEDIATED_PMU 2093eff95e17SKan Liang bool 2094eff95e17SKan Liang depends on GUEST_PERF_EVENTS 2095eff95e17SKan Liang 2096906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC 2097906010b2SPeter Zijlstra bool 2098906010b2SPeter Zijlstra help 2099906010b2SPeter Zijlstra See tools/perf/design.txt for details 2100906010b2SPeter Zijlstra 210157c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters" 21020793a61dSThomas Gleixner 2103cdd6c482SIngo Molnarconfig PERF_EVENTS 210457c0c15bSIngo Molnar bool "Kernel performance events and counters" 2105392d65a9SRobert Richter default y if PROFILING 2106cdd6c482SIngo Molnar depends on HAVE_PERF_EVENTS 2107e360adbeSPeter Zijlstra select IRQ_WORK 21080793a61dSThomas Gleixner help 210957c0c15bSIngo Molnar Enable kernel support for various performance events provided 211057c0c15bSIngo Molnar by software and hardware. 21110793a61dSThomas Gleixner 2112dd77038dSThadeu Lima de Souza Cascardo Software events are supported either built-in or via the 211357c0c15bSIngo Molnar use of generic tracepoints. 211457c0c15bSIngo Molnar 211557c0c15bSIngo Molnar Most modern CPUs support performance events via performance 211657c0c15bSIngo Molnar counter registers. These registers count the number of certain 21170793a61dSThomas Gleixner types of hw events: such as instructions executed, cachemisses 21180793a61dSThomas Gleixner suffered, or branches mis-predicted - without slowing down the 21190793a61dSThomas Gleixner kernel or applications. These registers can also trigger interrupts 21200793a61dSThomas Gleixner when a threshold number of events have passed - and can thus be 21210793a61dSThomas Gleixner used to profile the code that runs on that CPU. 21220793a61dSThomas Gleixner 212357c0c15bSIngo Molnar The Linux Performance Event subsystem provides an abstraction of 2124dd77038dSThadeu Lima de Souza Cascardo these software and hardware event capabilities, available via a 212557c0c15bSIngo Molnar system call and used by the "perf" utility in tools/perf/. It 21260793a61dSThomas Gleixner provides per task and per CPU counters, and it provides event 21270793a61dSThomas Gleixner capabilities on top of those. 21280793a61dSThomas Gleixner 21290793a61dSThomas Gleixner Say Y if unsure. 21300793a61dSThomas Gleixner 2131906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC 2132906010b2SPeter Zijlstra default n 2133906010b2SPeter Zijlstra bool "Debug: use vmalloc to back perf mmap() buffers" 2134cb307113SMichael Ellerman depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2135906010b2SPeter Zijlstra select PERF_USE_VMALLOC 2136906010b2SPeter Zijlstra help 2137906010b2SPeter Zijlstra Use vmalloc memory to back perf mmap() buffers. 2138906010b2SPeter Zijlstra 2139906010b2SPeter Zijlstra Mostly useful for debugging the vmalloc code on platforms 2140906010b2SPeter Zijlstra that don't require it. 2141906010b2SPeter Zijlstra 2142906010b2SPeter Zijlstra Say N if unsure. 2143906010b2SPeter Zijlstra 21440793a61dSThomas Gleixnerendmenu 21450793a61dSThomas Gleixner 2146091f6e26SDavid Howellsconfig SYSTEM_DATA_VERIFICATION 2147091f6e26SDavid Howells def_bool n 2148091f6e26SDavid Howells select SYSTEM_TRUSTED_KEYRING 2149091f6e26SDavid Howells select KEYS 2150091f6e26SDavid Howells select CRYPTO 2151d43de6c7SDavid Howells select CRYPTO_RSA 2152091f6e26SDavid Howells select ASYMMETRIC_KEY_TYPE 2153091f6e26SDavid Howells select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2154091f6e26SDavid Howells select ASN1 2155091f6e26SDavid Howells select OID_REGISTRY 2156091f6e26SDavid Howells select X509_CERTIFICATE_PARSER 2157091f6e26SDavid Howells select PKCS7_MESSAGE_PARSER 215882c04ff8SPeter Foley help 2159091f6e26SDavid Howells Provide PKCS#7 message verification using the contents of the system 2160091f6e26SDavid Howells trusted keyring to provide public keys. This then can be used for 2161091f6e26SDavid Howells module verification, kexec image verification and firmware blob 2162091f6e26SDavid Howells verification. 216382c04ff8SPeter Foley 2164125e5645SMathieu Desnoyersconfig PROFILING 2165b309a294SRobert Richter bool "Profiling support" 2166125e5645SMathieu Desnoyers help 2167125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 2168f8408264SViresh Kumar by profilers. 2169125e5645SMathieu Desnoyers 21702f7ab126SMiguel Ojedaconfig RUST 21712f7ab126SMiguel Ojeda bool "Rust support" 21722f7ab126SMiguel Ojeda depends on HAVE_RUST 21732f7ab126SMiguel Ojeda depends on RUST_IS_AVAILABLE 2174ac61506bSSami Tolvanen select EXTENDED_MODVERSIONS if MODVERSIONS 2175ac61506bSSami Tolvanen depends on !MODVERSIONS || GENDWARFKSYMS 2176f1385dc6SNeal Gompa depends on !GCC_PLUGIN_RANDSTRUCT 21772f7ab126SMiguel Ojeda depends on !RANDSTRUCT 21785daa0c35SMatthew Maurer depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 217923ef9d43SKees Cook depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 218023ef9d43SKees Cook select CFI_ICALL_NORMALIZE_INTEGERS if CFI 2181af6017b6SMiguel Ojeda depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2182f64e2f3aSMatthew Maurer depends on !KASAN_SW_TAGS 218393e34a0bSAlice Ryhl depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 21842f7ab126SMiguel Ojeda help 21852f7ab126SMiguel Ojeda Enables Rust support in the kernel. 21862f7ab126SMiguel Ojeda 21872f7ab126SMiguel Ojeda This allows other Rust-related options, like drivers written in Rust, 21882f7ab126SMiguel Ojeda to be selected. 21892f7ab126SMiguel Ojeda 21902f7ab126SMiguel Ojeda It is also required to be able to load external kernel modules 21912f7ab126SMiguel Ojeda written in Rust. 21922f7ab126SMiguel Ojeda 21932f7ab126SMiguel Ojeda See Documentation/rust/ for more information. 21942f7ab126SMiguel Ojeda 21952f7ab126SMiguel Ojeda If unsure, say N. 21962f7ab126SMiguel Ojeda 21972f7ab126SMiguel Ojedaconfig RUSTC_VERSION_TEXT 21982f7ab126SMiguel Ojeda string 21992f7ab126SMiguel Ojeda depends on RUST 22005134a335SMiguel Ojeda default "$(RUSTC_VERSION_TEXT)" 22015134a335SMiguel Ojeda help 22025134a335SMiguel Ojeda See `CC_VERSION_TEXT`. 22032f7ab126SMiguel Ojeda 22042f7ab126SMiguel Ojedaconfig BINDGEN_VERSION_TEXT 22052f7ab126SMiguel Ojeda string 22062f7ab126SMiguel Ojeda depends on RUST 22079e98db17SMiguel Ojeda # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2208c23d1f7eSMiguel Ojeda # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2209c23d1f7eSMiguel Ojeda # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2210c23d1f7eSMiguel Ojeda # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2211c23d1f7eSMiguel Ojeda # both fixed the issue). 2212aacf93e8SMasahiro Yamada default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 22132f7ab126SMiguel Ojeda 22145f87f112SIngo Molnar# 22155f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be 22165f87f112SIngo Molnar# dynamically changed for a probe function. 22175f87f112SIngo Molnar# 221897e1c18eSMathieu Desnoyersconfig TRACEPOINTS 22195f87f112SIngo Molnar bool 2220a363d27cSMathieu Desnoyers select TASKS_TRACE_RCU 222197e1c18eSMathieu Desnoyers 222289cde455SEric DeVoldersource "kernel/Kconfig.kexec" 222389cde455SEric DeVolder 222448a1b232SPasha Tatashinsource "kernel/liveupdate/Kconfig" 222548a1b232SPasha Tatashin 22261da177e4SLinus Torvaldsendmenu # General setup 22271da177e4SLinus Torvalds 22281572497cSChristoph Hellwigsource "arch/Kconfig" 22291572497cSChristoph Hellwig 2230ae81f9e3SChuck Ebbertconfig RT_MUTEXES 22316341e62bSChristoph Jaeger bool 22321c6f9ec0SSebastian Andrzej Siewior default y if PREEMPT_RT 2233ae81f9e3SChuck Ebbert 2234c8424e77SThiago Jung Bauermannconfig MODULE_SIG_FORMAT 2235c8424e77SThiago Jung Bauermann def_bool n 2236c8424e77SThiago Jung Bauermann select SYSTEM_DATA_VERIFICATION 2237c8424e77SThiago Jung Bauermann 223873b4fc92SChristophe Leroysource "kernel/module/Kconfig" 22396c9692e2SPeter Zijlstra 224098a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE 224198a79d6aSRusty Russell bool 224298a79d6aSRusty Russell help 22435f054e31SRusty Russell Back when each arch used to define their own cpu_online_mask and 22445f054e31SRusty Russell cpu_possible_mask, some of them chose to initialize cpu_possible_mask 224598a79d6aSRusty Russell with all 1s, and others with all 0s. When they were centralised, 224698a79d6aSRusty Russell it was better to provide this option than to break all the archs 2247692105b8SMatt LaPlante and have several arch maintainers pursuing me down dark alleys. 224898a79d6aSRusty Russell 22493a65dfe8SJens Axboesource "block/Kconfig" 2250e98c3202SAvi Kivity 2251e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 2252e98c3202SAvi Kivity bool 2253e260be67SPaul E. McKenney 225416295becSSteffen Klassertconfig PADATA 225516295becSSteffen Klassert depends on SMP 225616295becSSteffen Klassert bool 225716295becSSteffen Klassert 22584520c6a4SDavid Howellsconfig ASN1 22594520c6a4SDavid Howells tristate 22604520c6a4SDavid Howells help 22614520c6a4SDavid Howells Build a simple ASN.1 grammar compiler that produces a bytecode output 22624520c6a4SDavid Howells that can be interpreted by the ASN.1 stream decoder and used to 22634520c6a4SDavid Howells inform it as to what tags are to be expected in a stream and what 22644520c6a4SDavid Howells functions to call on what tags. 22654520c6a4SDavid Howells 22666beb0009SThomas Gleixnersource "kernel/Kconfig.locks" 2267e61938a9SMathieu Desnoyers 22680ebeea8cSDaniel Borkmannconfig ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 22690ebeea8cSDaniel Borkmann bool 22700ebeea8cSDaniel Borkmann 22714ff4c745SAndrea Parriconfig ARCH_HAS_PREPARE_SYNC_CORE_CMD 22724ff4c745SAndrea Parri bool 22734ff4c745SAndrea Parri 2274e61938a9SMathieu Desnoyersconfig ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2275e61938a9SMathieu Desnoyers bool 22761bd21c6cSDominik Brodowski 22771bd21c6cSDominik Brodowski# It may be useful for an architecture to override the definitions of the 22787303e30eSDominik Brodowski# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 22797303e30eSDominik Brodowski# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 22807303e30eSDominik Brodowski# different calling convention for syscalls. They can also override the 22817303e30eSDominik Brodowski# macros for not-implemented syscalls in kernel/sys_ni.c and 22827303e30eSDominik Brodowski# kernel/time/posix-stubs.c. All these overrides need to be available in 22837303e30eSDominik Brodowski# <asm/syscall_wrapper.h>. 22841bd21c6cSDominik Brodowskiconfig ARCH_HAS_SYSCALL_WRAPPER 22851bd21c6cSDominik Brodowski def_bool n 2286