README (for LKMM Documentation)

Literal include of tools/memory-model/Documentation/README.

---

It has been said that successful communication requires first identifying
what your audience knows and then building a bridge from their current
knowledge to what they need to know.  Unfortunately, the expected
Linux-kernel memory model (LKMM) audience might be anywhere from novice
to expert both in kernel hacking and in understanding LKMM.

This document therefore points out a number of places to start reading,
depending on what you know and what you would like to learn.  Please note
that the documents later in this list assume that the reader understands
the material provided by documents earlier in this list.

If LKMM-specific terms lost you, glossary.txt might help you.

o       You are new to Linux-kernel concurrency: simple.txt

o       You have some background in Linux-kernel concurrency, and would
        like an overview of the types of low-level concurrency primitives
        that the Linux kernel provides:  ordering.txt

        Here, "low level" means atomic operations to single variables.

o       You are familiar with the Linux-kernel concurrency primitives
        that you need, and just want to get started with LKMM litmus
        tests:  litmus-tests.txt

o       You need to locklessly access shared variables that are otherwise
        protected by a lock: locking.txt

        This locking.txt file expands on the "Locking" section in
        recipes.txt, but is self-contained.

o       You are familiar with Linux-kernel concurrency, and would
        like a detailed intuitive understanding of LKMM, including
        situations involving more than two threads:  recipes.txt

o       You would like a detailed understanding of what your compiler can
        and cannot do to control dependencies:  control-dependencies.txt

o       You would like to mark concurrent normal accesses to shared
        variables so that intentional "racy" accesses can be properly
        documented, especially when you are responding to complaints
        from KCSAN:  access-marking.txt

o       You are familiar with Linux-kernel concurrency and the use of
        LKMM, and would like a quick reference:  cheatsheet.txt

o       You are familiar with Linux-kernel concurrency and the use
        of LKMM, and would like to learn about LKMM's requirements,
        rationale, and implementation:  explanation.txt and
        herd-representation.txt

o       You are interested in the publications related to LKMM, including
        hardware manuals, academic literature, standards-committee
        working papers, and LWN articles:  references.txt


====================
DESCRIPTION OF FILES
====================

README
        This file.

access-marking.txt
        Guidelines for marking intentionally concurrent accesses to
        shared memory.

cheatsheet.txt
        Quick-reference guide to the Linux-kernel memory model.

control-dependencies.txt
        Guide to preventing compiler optimizations from destroying
        your control dependencies.

explanation.txt
        Detailed description of the memory model.

glossary.txt
        Brief definitions of LKMM-related terms.

herd-representation.txt
        The (abstract) representation of the Linux-kernel concurrency
        primitives in terms of events.

litmus-tests.txt
        The format, features, capabilities, and limitations of the litmus
        tests that LKMM can evaluate.

locking.txt
        Rules for accessing lock-protected shared variables outside of
        their corresponding critical sections.

ordering.txt
        Overview of the Linux kernel's low-level memory-ordering
        primitives by category.

recipes.txt
        Common memory-ordering patterns.

references.txt
        Background information.

simple.txt
        Starting point for someone new to Linux-kernel concurrency.
        And also a reminder of the simpler approaches to concurrency!