Changes in README

fa9e35a0 - tools/memory-model/README: Fix typo

Tue, 25 Feb 2025 09:39:58 +0000

tools/memory-model/README: Fix typoFix a trivial typo.Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

fafa1806 - tools/memory-model: Switch to softcoded herd7 tags

Mon, 30 Sep 2024 10:57:09 +0000

tools/memory-model: Switch to softcoded herd7 tagsA new version of herd7 provides a -lkmmv2 switch which overrides the old herd7behavior of simply ignoring any softcoded tags in the .def and .bell files. Weport LKMM to this version of herd7 by providing the switch in linux-kernel.cfgand reporting an error if the LKMM is used without this switch.To preserve the semantics of LKMM, we also softcode the Noreturn tag on atomicRMW which do not return a value and define atomic_add_unless with an Mb tag inlinux-kernel.def.We update the herd-representation.txt accordingly and clarify some of theresulting combinations.Co-developed-by: Hernan Ponce de Leon Signed-off-by: Hernan Ponce de Leon Signed-off-by: Jonas Oberhauser Signed-off-by: Paul E. McKenney Reviewed-by: Boqun Feng Tested-by: Boqun Feng Tested-by: Akira Yokosawa # herdtools7.7.58 List of files: /linux-6.15/tools/memory-model/README

5b759db4 - tools/memory-model/README: Update klitmus7 compat table

Mon, 02 May 2022 12:05:09 +0000

tools/memory-model/README: Update klitmus7 compat tableEXPORT_SYMBOL of do_exec() was removed in v5.17. Unfortunately,kernel modules from klitmus7 7.56 have do_exec() at the end ofeach kthread.herdtools7 7.56.1 has addressed the issue.Update the compatibility table accordingly.Signed-off-by: Akira Yokosawa Cc: Luc Maranget Cc: Jade Alglave Cc: stable@vger.kernel.org # v5.17+Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

b47c05ec - tools/memory-model: doc: Describe the requirement of the litmus-tests directory

Mon, 25 Oct 2021 14:54:15 +0000

tools/memory-model: doc: Describe the requirement of the litmus-tests directoryIt's better that we have some "standard" about which test should be putin the litmus-tests directory because it helps future contributorsunderstand whether they should work on litmus-tests in kernel or Paul'sGitHub repo. Therefore explain a little bit on what a "representative"litmus test is.Signed-off-by: Boqun Feng Acked-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

3d5c7032 - tools/memory-model: Fix typo in klitmus7 compatibility table

Sat, 28 Nov 2020 05:32:15 +0000

tools/memory-model: Fix typo in klitmus7 compatibility tableklitmus7 of herdtools7 7.48 or earlier depends on ACCESS_ONCE(),which was removed in Linux v4.15.Fix the obvious typo in the table.Fixes: d075a78a5ab1 ("tools/memory-model/README: Expand dependency of klitmus7")Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

ab8bcad6 - tools/memory-model: Move Documentation description to Documentation/README

Tue, 04 Aug 2020 21:00:17 +0000

tools/memory-model: Move Documentation description to Documentation/READMEThis commit moves the descriptions of the files residing intools/memory-model/Documentation to a README file in that directory,leaving behind the description of tools/memory-model/Documentation/READMEitself. After this change, tools/memory-model/Documentation/READMEprovides a guide to the files in the tools/memory-model/Documentationdirectory, guiding people with different skills and needs to the mostappropriate starting point.Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

0b8c06b7 - tools/memory-model: Add a simple entry point document

Tue, 04 Aug 2020 17:58:55 +0000

tools/memory-model: Add a simple entry point documentCurrent LKMM documentation assumes that the reader already understandsconcurrency in the Linux kernel, which won't necessarily always be thecase. This commit supplies a simple.txt file that provides a startingpoint for someone who is new to concurrency in the Linux kernel.That said, this file might also useful as a reminder to experienceddevelopers of simpler approaches to dealing with concurrency.Link: Link: https://lwn.net/Articles/827180/[ paulmck: Apply feedback from Joel Fernandes. ]Co-developed-by: Dave Chinner Signed-off-by: Dave Chinner Co-developed-by: Paul E. McKenney Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

984f272b - tools/memory-model: Improve litmus-test documentation

Tue, 04 Aug 2020 00:19:54 +0000

tools/memory-model: Improve litmus-test documentationThe current LKMM documentation says very little about litmus tests, andworse yet directs people to the herd7 documentation for more information.Now, the herd7 documentation is quite voluminous and educational,but it is intended for people creating and modifying memory models,not those attempting to use them.This commit therefore updates README and creates a litmus-tests.txtfile that gives an overview of litmus-test format and describes ways ofmodeling various special cases, illustrated with numerous examples.[ paulmck: Add Alan Stern feedback. ][ paulmck: Apply Dave Chinner feedback. ][ paulmck: Apply Andrii Nakryiko feedback. ][ paulmck: Apply Johannes Weiner feedback. ]Link: https://lwn.net/Articles/827180/Reported-by: Dave Chinner Acked-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

2bfa5c62 - tools/memory-model/README: Mention herdtools7 7.56 in compatibility table

Tue, 23 Jun 2020 21:56:43 +0000

tools/memory-model/README: Mention herdtools7 7.56 in compatibility tableherdtools7 7.56 is going to be released in the week of 22 Jun 2020.This commit therefore adds the exact version in the compatibility table.Acked-by: Andrea Parri Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

d075a78a - tools/memory-model/README: Expand dependency of klitmus7

Sun, 31 May 2020 11:04:32 +0000

tools/memory-model/README: Expand dependency of klitmus7klitmus7 is independent of the memory model but depends on thebuild-target kernel release.It occasionally lost compatibility due to kernel API changes [1, 2, 3].It was remedied in a backwards-compatible manner respectively [4, 5, 6].Reflect this fact in README.[1]: b899a850431e ("compiler.h: Remove ACCESS_ONCE()")[2]: 0bb95f80a38f ("Makefile: Globally enable VLA warning")[3]: d56c0d45f0e2 ("proc: decouple proc from VFS with "struct proc_ops"")[4]: https://github.com/herd/herdtools7/commit/e87d7f9287d1 ("klitmus: Use WRITE_ONCE and READ_ONCE in place of deprecated ACCESS_ONCE")[5]: https://github.com/herd/herdtools7/commit/a0cbb10d02be ("klitmus: Avoid variable length array")[6]: https://github.com/herd/herdtools7/commit/46b9412d3a58 ("klitmus: Linux kernel v5.6.x compat")NOTE: [5] was ahead of herdtools7 7.53, which did not make anofficial release. Code generated by klitmus7 without [5] can still bebuilt targeting Linux 4.20--5.5 if you don't care VLA warnings.Acked-by: Andrea Parri Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

4a9cc65f - tools/memory-model: Add an exception for limitations on _unless() family

Thu, 26 Mar 2020 02:40:19 +0000

tools/memory-model: Add an exception for limitations on _unless() familyAccording to Luc, atomic_add_unless() is directly provided by herd7,therefore it can be used in litmus tests. So change the limitationsection in README to unlimit the use of atomic_add_unless().Cc: Luc Maranget Acked-by: Andrea Parri Reviewed-by: Joel Fernandes (Google) Signed-off-by: Boqun Feng Signed-off-by: Paul E. McKenney List of files: /linux-6.15/tools/memory-model/README

6738ff85 - tools/memory-model: Update the informal documentation

Sat, 29 Jun 2019 21:10:44 +0000

tools/memory-model: Update the informal documentationThe formal memory consistency model has added support for plain accesses(and data races). While updating the informal documentation to describethis addition to the model is highly desirable and important future work,update the informal documentation to at least acknowledge such addition.Signed-off-by: Andrea Parri Cc: Will Deacon Cc: Peter Zijlstra Cc: Boqun Feng Cc: Nicholas Piggin Cc: David Howells Cc: Jade Alglave Cc: Luc Maranget Cc: "Paul E. McKenney" Cc: Akira Yokosawa Cc: Daniel Lustig Signed-off-by: Paul E. McKenney Acked-by: Alan Stern List of files: /linux-6.15/tools/memory-model/README

034fb712 - tools/memory-model: Avoid duplicating herdtools versions

Thu, 31 Jan 2019 16:08:40 +0000

tools/memory-model: Avoid duplicating herdtools versionsCurrently, herdtools version information appears no fewer than threetimes in the LKMM source, which is difficult to maintain. This committherefore places the required version in one place, namely thetools/memory-model/README file.Signed-off-by: Andrea Parri Signed-off-by: Paul E. McKenney Acked-by: Alan Stern List of files: /linux-6.15/tools/memory-model/README

ad9fd20b - tools/memory-model: Update README for addition of SRCU

Mon, 26 Nov 2018 22:26:43 +0000

tools/memory-model: Update README for addition of SRCUThis commit updates the section on LKMM limitations to no longer saythat SRCU is not modeled, but instead describe how LKMM's modeling ofSRCU departs from the Linux-kernel implementation.TL;DR: There is no known valid use case that cares about the Linuxkernel's ability to have partially overlapping SRCU read-side criticalsections.Signed-off-by: Paul E. McKenney Acked-by: Andrea Parri List of files: /linux-6.15/tools/memory-model/README

b02eb5b0 - tools/memory-model: Add scripts to check github litmus tests

Mon, 03 Dec 2018 23:04:50 +0000

tools/memory-model: Add scripts to check github litmus testsThe https://github.com/paulmckrcu/litmus repository contains a largenumber of C-language litmus tests that include "Result:" commentspredicting the verification result. This commit adds a number of scriptsthat run tests on these litmus tests:checkghlitmus.sh: Runs all litmus tests in the https://github.com/paulmckrcu/litmus archive that are C-language and that have "Result:" comment lines documenting expected results, comparing the actual results to those expected. Clones the repository if it has not already been cloned into the "tools/memory-model/litmus" directory.initlitmushist.sh Run all litmus tests having no more than the specified number of processes given a specified timeout, recording the results in .litmus.out files. Clones the repository if it has not already been cloned into the "tools/memory-model/litmus" directory.newlitmushist.sh For all new or updated litmus tests having no more than the specified number of processes given a specified timeout, run and record the results in .litmus.out files.checklitmushist.sh Run all litmus tests having .litmus.out files from previous initlitmushist.sh or newlitmushist.sh runs, comparing the herd output to that of the original runs.The above scripts will run litmus tests concurrently, by default withone job per available CPU. Giving any of these scripts the --helpargument will cause them to print usage information.This commit also adds a number of helper scripts that are not intendedto be invoked from the command line:cmplitmushist.sh: Compare the output of two different runs of the same litmus test.judgelitmus.sh: Compare the output of a litmus test to its "Result:" comment line.parseargs.sh: Parse command-line arguments.runlitmushist.sh: Run the litmus tests whose pathnames are provided one per line on standard input.While in the area, this commit also makes the existing checklitmus.shand checkalllitmus.sh scripts use parseargs.sh in order to provide abit of uniformity. In addition, per-litmus-test status output is directedto stdout, while end-of-test summary information is directed to stderr.Finally, the error flag standardizes on "!!!" to assist those familiarwith rcutorture output.The defaults for the parseargs.sh arguments may be overridden by usingenvironment variables: LKMM_DESTDIR for --destdir, LKMM_HERD_OPTIONSfor --herdoptions, LKMM_JOBS for --jobs, LKMM_PROCS for --procs, andLKMM_TIMEOUT for --timeout.[ paulmck: History-check summary-line changes per Alan Stern feedback. ]Signed-off-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akiyks@gmail.comCc: boqun.feng@gmail.comCc: dhowells@redhat.comCc: j.alglave@ucl.ac.ukCc: linux-arch@vger.kernel.orgCc: luc.maranget@inria.frCc: npiggin@gmail.comCc: parri.andrea@gmail.comCc: stern@rowland.harvard.eduCc: will.deacon@arm.comLink: http://lkml.kernel.org/r/20181203230451.28921-2-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README

d8fa25c4 - tools/memory-model: Add more LKMM limitations

Wed, 26 Sep 2018 18:29:19 +0000

tools/memory-model: Add more LKMM limitationsThis commit adds more detail about compiler optimizations andnot-yet-modeled Linux-kernel APIs.Signed-off-by: Paul E. McKenney Reviewed-by: Andrea Parri Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: akiyks@gmail.comCc: boqun.feng@gmail.comCc: dhowells@redhat.comCc: j.alglave@ucl.ac.ukCc: linux-arch@vger.kernel.orgCc: luc.maranget@inria.frCc: npiggin@gmail.comCc: parri.andrea@gmail.comCc: stern@rowland.harvard.eduCc: will.deacon@arm.comLink: http://lkml.kernel.org/r/20180926182920.27644-4-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README

71b7ff5e - tools/memory-model: Rename litmus tests to comply to norm7

Mon, 16 Jul 2018 18:06:05 +0000

tools/memory-model: Rename litmus tests to comply to norm7norm7 produces the 'normalized' name of a litmus test, when the testcan be generated from a single cycle that passes through each processexactly once. The commit renames such tests in order to comply to thenaming scheme implemented by this tool.Signed-off-by: Andrea Parri Signed-off-by: Paul E. McKenney Acked-by: Alan Stern Cc: Akira Yokosawa Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.orgCc: parri.andrea@gmail.comLink: http://lkml.kernel.org/r/20180716180605.16115-14-paulmck@linux.vnet.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README

5b62832c - tools/memory-model: Update required version of herdtools7

Mon, 14 May 2018 23:33:41 +0000

tools/memory-model: Update required version of herdtools7Code generated by klitmus7 version 7.48 doesn't compile with kernelheader of 4.15 and later due to the absence of ACCESS_ONCE().As the issue has been resolved in herdtools7 7.49, bump the requiredversion number in README.Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney Cc: Alan Stern Cc: Andrea Parri Cc: Andrew Morton Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.orgLink: http://lkml.kernel.org/r/1526340837-12222-3-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README

d095c12c - tools/memory-model: Remove mention of docker/gentoo image

Wed, 07 Mar 2018 17:27:38 +0000

tools/memory-model: Remove mention of docker/gentoo imageBecause the docker and gentoo images haven't been updated in quite sometime, they are likely to provide more confusion than help. This committherefore removes mention of them from the README file.Reported-by: Alan Stern Signed-off-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akiyks@gmail.comCc: boqun.feng@gmail.comCc: dhowells@redhat.comCc: j.alglave@ucl.ac.ukCc: linux-arch@vger.kernel.orgCc: luc.maranget@inria.frCc: npiggin@gmail.comCc: parri.andrea@gmail.comCc: will.deacon@arm.comLink: http://lkml.kernel.org/r/1520443660-16858-2-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README

8f7f2fbd - tools/memory-model: Add required herd7 version to README file

Tue, 20 Feb 2018 23:25:09 +0000

tools/memory-model: Add required herd7 version to README fileLKMM and the herd7 tool are co-evolving, and out-of-date herd7 toolsproduce inaccurate results, often with no obvious error messages. Thiscommit therefore adds the required herd7 version to the LKMM README file.Longer term, it would be good if .cat files could specify the requiredversion in a manner allowing herd7 to produce clear diagnostics.Suggested-by: Akira Yokosawa Signed-off-by: Paul E. McKenney Acked-by: Peter Zijlstra Cc: Linus Torvalds Cc: Thomas Gleixner Cc: boqun.feng@gmail.comCc: dhowells@redhat.comCc: j.alglave@ucl.ac.ukCc: linux-arch@vger.kernel.orgCc: luc.maranget@inria.frCc: nborisov@suse.comCc: npiggin@gmail.comCc: parri.andrea@gmail.comCc: stern@rowland.harvard.eduCc: will.deacon@arm.comLink: http://lkml.kernel.org/r/1519169112-20593-9-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/tools/memory-model/README