Changes in Makefile

4e88ec4a - rcuperf: Change rcuperf to rcuscale

Wed, 12 Aug 2020 04:18:12 +0000

rcuperf: Change rcuperf to rcuscaleThis commit further avoids conflation of rcuperf with the kernel's perffeature by renaming kernel/rcu/rcuperf.c to kernel/rcu/rcuscale.c, andalso by similarly renaming the functions and variables inside this file.This has the side effect of changing the names of the kernel bootparameters, so kernel-parameters.txt and ver_functions.sh are alsoupdated. The rcutorture --torture type was also updated from rcuperfto rcuscale.[ paulmck: Fix bugs located by Stephen Rothwell. ]Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

1fbeb3a8 - refperf: Rename refperf.c to refscale.c and change internal names

Wed, 17 Jun 2020 18:53:53 +0000

refperf: Rename refperf.c to refscale.c and change internal namesThis commit further avoids conflation of refperf with the kernel's perffeature by renaming kernel/rcu/refperf.c to kernel/rcu/refscale.c,and also by similarly renaming the functions and variables insidethis file. This has the side effect of changing the names of thekernel boot parameters, so kernel-parameters.txt and ver_functions.share also updated.The rcutorture --torture type remains refperf, and this will beaddressed in a separate commit.Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

8e4ec3d0 - refperf: Rename RCU_REF_PERF_TEST to RCU_REF_SCALE_TEST

Wed, 17 Jun 2020 18:33:54 +0000

refperf: Rename RCU_REF_PERF_TEST to RCU_REF_SCALE_TESTThe old Kconfig option name is all too easy to conflate with theunrelated "perf" feature, so this commit renames RCU_REF_PERF_TEST toRCU_REF_SCALE_TEST.Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

653ed64b - refperf: Add a test to measure performance of read-side synchronization

Mon, 25 May 2020 04:36:48 +0000

refperf: Add a test to measure performance of read-side synchronizationAdd a test for comparing the performance of RCU with various read-sidesynchronization mechanisms. The test has proved useful for collectingdata and performing these comparisons.Currently RCU, SRCU, reader-writer lock, reader-writer semaphore andreference counting can be measured using refperf.perf_type parameter.Each invocation of the test runs measures performance of a specificmechanism.The maximum number of CPUs to concurrently run readers on is chosen bythe test itself and is 75% of the total number of CPUs. So if you had 24CPUs, the test runs with a maximum of 18 parallel readers.A number of experiments are conducted, and in each experiment, thenumber of readers is increased by 1, upto the 75% of CPUs mark. Duringeach experiment, all readers execute an empty loop with refperf.loopsiterations and time the total loop duration. This is then averaged.Example output:Parameters "refperf.perf_type=srcu refperf.loops=2000000" looks like:[ 3.347133] srcu-ref-perf:[ 3.347133] Threads Time(ns)[ 3.347133] 1 36[ 3.347133] 2 34[ 3.347133] 3 34[ 3.347133] 4 34[ 3.347133] 5 33[ 3.347133] 6 33[ 3.347133] 7 33[ 3.347133] 8 33[ 3.347133] 9 33[ 3.347133] 10 33[ 3.347133] 11 33[ 3.347133] 12 33[ 3.347133] 13 33[ 3.347133] 14 33[ 3.347133] 15 32[ 3.347133] 16 33[ 3.347133] 17 33[ 3.347133] 18 34Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

8a7e8f51 - rcu: Provide debug symbols and line numbers in KCSAN runs

Fri, 03 Jan 2020 00:48:05 +0000

rcu: Provide debug symbols and line numbers in KCSAN runsThis commit adds "-g -fno-omit-frame-pointer" to ease interpretationof KCSAN output, but only for CONFIG_KCSAN=y kerrnels.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

b3e627d3 - rcu: Make PREEMPT_RCU be a modifier to TREE_RCU

Tue, 15 Oct 2019 02:55:57 +0000

rcu: Make PREEMPT_RCU be a modifier to TREE_RCUCurrently PREEMPT_RCU and TREE_RCU are mutually exclusive Kconfigoptions. But PREEMPT_RCU actually specifies a kind of TREE_RCU,namely a preemptible TREE_RCU. This commit therefore makes PREEMPT_RCUbe a modifer to the TREE_RCU Kconfig option. This has the benefit ofsimplifying several of the #if expressions that formerly needed tocheck both, but now need only check one or the other.Signed-off-by: Lai Jiangshan Signed-off-by: Lai Jiangshan Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

b2441318 - License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Wed, 01 Nov 2017 14:07:57 +0000

License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseMany source files in the tree are missing licensing information, whichmakes it harder for compliance tools to determine the correct license.By default all files without license information are under the defaultlicense of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'SPDX license identifier. The SPDX identifier is a legally bindingshorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart andPhilippe Ombredanne.How this work was done:Patches were generated and checked against linux-4.14-rc6 for a subset ofthe use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up caseswhere non-standard license headers were used, and references to licensehad to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied toa file was done in a spreadsheet of side by side results from of theoutput of two independent scanners (ScanCode & Windriver) producing SPDXtag:value files created by Philippe Ombredanne. Philippe prepared thebase worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 filesassessed. Kate Stewart did a file by file comparison of the scannerresults in the spreadsheet to determine which SPDX license identifier(s)to be applied to the file. She confirmed any determination that was notimmediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines).All documentation files were explicitly excluded.The following heuristics were used to determine which SPDX licenseidentifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time.In total, over 70 hours of logged manual review was done on thespreadsheet to determine the SPDX license identifiers to apply to thesource files by Kate, Philippe, Thomas and, in some cases, confirmationby lawyers working with the Linux Foundation.Kate also obtained a third independent scan of the 4.13 code base fromFOSSology, and compared selected files where the other two scannersdisagreed against that SPDX file, to see if there was new insights. TheWindriver scanner is based on an older version of FOSSology in part, sothey are related.Thomas did random spot checks in about 500 files from the spreadsheetsfor the uapi headers and agreed with SPDX license identifier in thefiles he inspected. For the non-uapi files Thomas did random spot checksin about 15000 files.In initial set of patches against 4.14-rc6, 3 files were found to havecopy/paste license identifier errors, and have been fixed to reflect thecorrect identifier.Additionally Philippe spent 10 hours this week doing a detailed manualinspection and review of the 12,461 patched files from the initial patchversion early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correctThis produced a worksheet with 20 files needing minor correction. Thisworksheet was then exported into 3 different .csv files for thedifferent types of files to be modified.These .csv files were then reviewed by Greg. Thomas wrote a script toparse the csv files and add the proper SPDX tag to the file, in theformat that the file expected. This script was further refined by Gregbased on the output to detect more types of files automatically and todistinguish between header and source .c files (which need differentcomment types.) Finally Greg ran the script using the .csv files togenerate the patches.Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman List of files: /linux-6.15/kernel/rcu/Makefile

ae91aa0a - rcu: Remove debugfs tracing

Mon, 15 May 2017 22:30:32 +0000

rcu: Remove debugfs tracingRCU's debugfs tracing used to be the only reasonable low-level debuginformation available, but ftrace and event tracing has since surpassedthe RCU debugfs level of usefulness. This commit therefore removesRCU's debugfs tracing.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

bd8cc5a0 - srcu: Remove Classic SRCU

Mon, 15 May 2017 21:57:01 +0000

srcu: Remove Classic SRCUClassic SRCU was only ever intended to be a fallback in case of issueswith Tree/Tiny SRCU, and the latter two are doing quite well in testing.This commit therefore removes Classic SRCU.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

98059b98 - rcu: Separately compile large rcu_segcblist functions

Tue, 02 May 2017 13:30:12 +0000

rcu: Separately compile large rcu_segcblist functionsThis commit creates a new kernel/rcu/rcu_segcblist.c file thatcontains non-trivial segcblist functions. Trivial functionsremain as static inline functions in kernel/rcu/rcu_segcblist.hReported-by: Linus Torvalds Signed-off-by: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner List of files: /linux-6.15/kernel/rcu/Makefile

dad81a20 - srcu: Introduce CLASSIC_SRCU Kconfig option

Sun, 26 Mar 2017 00:23:44 +0000

srcu: Introduce CLASSIC_SRCU Kconfig optionThe TREE_SRCU rewrite is large and a bit on the non-simple side, sothis commit helps reduce risk by allowing the old v4.11 SRCU algorithmto be selected using a new CLASSIC_SRCU Kconfig option that dependson RCU_EXPERT. The default is to use the new TREE_SRCU and TINY_SRCUalgorithms, in order to help get these the testing that they need.However, if your users do not require the update-side scalability thatis to be provided by TREE_SRCU, select RCU_EXPERT and then CLASSIC_SRCUto revert back to the old classic SRCU algorithm.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

d8be8173 - srcu: Create a tiny SRCU

Sat, 25 Mar 2017 16:59:38 +0000

srcu: Create a tiny SRCUIn response to automated complaints about modifications to SRCUincreasing its size, this commit creates a tiny SRCU that isused in SMP=n && PREEMPT=n builds.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

8704baab - rcutorture: Add RCU grace-period performance tests

Fri, 01 Jan 2016 02:33:22 +0000

rcutorture: Add RCU grace-period performance testsThis commit adds a new rcuperf module that carries out simple performancetests of RCU grace periods.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

5c9a8750 - kernel: add kcov code coverage

Tue, 22 Mar 2016 21:27:30 +0000

kernel: add kcov code coveragekcov provides code coverage collection for coverage-guided fuzzing(randomized testing). Coverage-guided fuzzing is a testing techniquethat uses coverage feedback to determine new interesting inputs to asystem. A notable user-space example is AFL(http://lcamtuf.coredump.cx/afl/). However, this technique is notwidely used for kernel testing due to missing compiler and kernelsupport.kcov does not aim to collect as much coverage as possible. It aims tocollect more or less stable coverage that is function of syscall inputs.To achieve this goal it does not collect coverage in soft/hardinterrupts and instrumentation of some inherently non-deterministic ornon-interesting parts of kernel is disbled (e.g. scheduler, locking).Currently there is a single coverage collection mode (tracing), but theAPI anticipates additional collection modes. Initially I alsoimplemented a second mode which exposes coverage in a fixed-size hashtable of counters (what Quentin used in his original patch). I'vedropped the second mode for simplicity.This patch adds the necessary support on kernel side. The complimentarycompiler support was added in gcc revision 231296.We've used this support to build syzkaller system call fuzzer, which hasfound 90 kernel bugs in just 2 months: https://github.com/google/syzkaller/wiki/Found-BugsWe've also found 30+ bugs in our internal systems with syzkaller.Another (yet unexplored) direction where kcov coverage would greatlyhelp is more traditional "blob mutation". For example, mounting arandom blob as a filesystem, or receiving a random blob over wire.Why not gcov. Typical fuzzing loop looks as follows: (1) resetcoverage, (2) execute a bit of code, (3) collect coverage, repeat. Atypical coverage can be just a dozen of basic blocks (e.g. an invalidinput). In such context gcov becomes prohibitively expensive asreset/collect coverage steps depend on total number of basicblocks/edges in program (in case of kernel it is about 2M). Cost ofkcov depends only on number of executed basic blocks/edges. On top ofthat, kernel requires per-thread coverage because there are alwaysbackground threads and unrelated processes that also produce coverage.With inlined gcov instrumentation per-thread coverage is not possible.kcov exposes kernel PCs and control flow to user-space which isinsecure. But debugfs should not be mapped as user accessible.Based on a patch by Quentin Casasnovas.[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode'][akpm@linux-foundation.org: unbreak allmodconfig][akpm@linux-foundation.org: follow x86 Makefile layout standards]Signed-off-by: Dmitry Vyukov Reviewed-by: Kees Cook Cc: syzkaller Cc: Vegard Nossum Cc: Catalin Marinas Cc: Tavis Ormandy Cc: Will Deacon Cc: Quentin Casasnovas Cc: Kostya Serebryany Cc: Eric Dumazet Cc: Alexander Potapenko Cc: Kees Cook Cc: Bjorn Helgaas Cc: Sasha Levin Cc: David Drysdale Cc: Ard Biesheuvel Cc: Andrey Ryabinin Cc: Kirill A. Shutemov Cc: Jiri Slaby Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds List of files: /linux-6.15/kernel/rcu/Makefile

cc44ca84 - rcu: Create rcu_sync infrastructure

Fri, 21 Aug 2015 17:42:44 +0000

rcu: Create rcu_sync infrastructureThe rcu_sync infrastructure can be thought of as infrastructure to beused to implement reader-writer primitives having extremely lightweightreaders during times when there are no writers. The first use is inthe percpu_rwsem used by the VFS subsystem.This infrastructure is functionally equivalent to struct rcu_sync_struct { atomic_t counter; }; /* Check possibility of fast-path read-side operations. */ static inline bool rcu_sync_is_idle(struct rcu_sync_struct *rss) { return atomic_read(&rss->counter) == 0; } /* Tell readers to use slowpaths. */ static inline void rcu_sync_enter(struct rcu_sync_struct *rss) { atomic_inc(&rss->counter); synchronize_sched(); } /* Allow readers to once again use fastpaths. */ static inline void rcu_sync_exit(struct rcu_sync_struct *rss) { synchronize_sched(); atomic_dec(&rss->counter); }The main difference is that it records the state and only callssynchronize_sched() if required. At least some of the calls tosynchronize_sched() will be optimized away when rcu_sync_enter() andrcu_sync_exit() are invoked repeatedly in quick succession.Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett List of files: /linux-6.15/kernel/rcu/Makefile

83fe27ea - rcu: Make SRCU optional by using CONFIG_SRCU

Fri, 05 Dec 2014 16:24:45 +0000

rcu: Make SRCU optional by using CONFIG_SRCUSRCU is not necessary to be compiled by default in all cases. For tinificationefforts not compiling SRCU unless necessary is desirable.The current patch tries to make compiling SRCU optional by introducing a newKconfig option CONFIG_SRCU which is selected when any of the components makinguse of SRCU are selected.If we do not select CONFIG_SRCU, srcu.o will not be compiled at all. text data bss dec hex filename 2007 0 0 2007 7d7 kernel/rcu/srcu.oSize of arch/powerpc/boot/zImage changes from text data bss dec hex filename 831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before 829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : afterso the savings are about ~2000 bytes.Signed-off-by: Pranith Kumar CC: Paul E. McKenney CC: Josh Triplett CC: Lai Jiangshan Signed-off-by: Paul E. McKenney [ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ] List of files: /linux-6.15/kernel/rcu/Makefile

28f6569a - rcu: Remove redundant TREE_PREEMPT_RCU config option

Mon, 22 Sep 2014 18:00:48 +0000

rcu: Remove redundant TREE_PREEMPT_RCU config optionPREEMPT_RCU and TREE_PREEMPT_RCU serve the same function afterTINY_PREEMPT_RCU has been removed. This patch removes TREE_PREEMPT_RCUand uses PREEMPT_RCU config option in its place.Signed-off-by: Pranith Kumar Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

51b1130e - rcutorture: Abstract rcu_torture_random()

Mon, 27 Jan 2014 19:49:39 +0000

rcutorture: Abstract rcu_torture_random()Because rcu_torture_random() will be used by the locking equivalent torcutorture, pull it out into its own module. This new module cannotbe separately configured, instead, use the Kconfig "select" statementfrom the Kconfig options of tests depending on it.Suggested-by: Rusty Russell Signed-off-by: Paul E. McKenney List of files: /linux-6.15/kernel/rcu/Makefile

4102adab - rcu: Move RCU-related source code to kernel/rcu directory

Wed, 09 Oct 2013 03:23:47 +0000

rcu: Move RCU-related source code to kernel/rcu directorySigned-off-by: Paul E. McKenney Reviewed-by: Ingo Molnar List of files: /linux-6.15/kernel/rcu/Makefile