On Tue, Sep 01, 2020 at 07:34:20AM +0900, Akira Yokosawa wrote: > On Mon, 31 Aug 2020 11:20:36 -0700, paulmck@xxxxxxxxxx wrote: > > From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> > > > > The Linux kernel has a number of categories of ordering primitives, which > > are recorded in the LKMM implementation and hinted at by cheatsheet.txt. > > But there is no overview of these categories, and such an overview > > is needed in order to understand multithreaded LKMM litmus tests. > > This commit therefore adds an ordering.txt as well as extracting a > > control-dependencies.txt from memory-barriers.txt. It also updates the > > README file. > > > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> > > --- > > tools/memory-model/Documentation/README | 24 +- > > tools/memory-model/Documentation/ordering.txt | 462 ++++++++++++++++++++++++++ > > tools/memory-model/control-dependencies.txt | 256 ++++++++++++++ > > 3 files changed, 740 insertions(+), 2 deletions(-) > > create mode 100644 tools/memory-model/Documentation/ordering.txt > > create mode 100644 tools/memory-model/control-dependencies.txt > > Hi Paul, > > Didn't you mean to put control-dependencies.txt under tools/memory-model/Documentation/ ? Indeed I did, good catch, thank you! Thanx, Paul > Thanks, Akira > > > > > diff --git a/tools/memory-model/Documentation/README b/tools/memory-model/Documentation/README > > index 4326603..16177aa 100644 > > --- a/tools/memory-model/Documentation/README > > +++ b/tools/memory-model/Documentation/README > > @@ -8,10 +8,19 @@ number of places. > > > > This document therefore describes a number of places to start reading > > the documentation in this directory, depending on what you know and what > > -you would like to learn: > > +you would like to learn. These are cumulative, that is, understanding > > +of the documents earlier in this list is required by the documents later > > +in this list. > > > > 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 are provided: ordering.txt > > + > > + Here, "low level" means atomic operations to single locations in > > + memory. > > + > > o You are familiar with the concurrency facilities that you > > need, and just want to get started with LKMM litmus tests: > > litmus-tests.txt > > @@ -20,6 +29,9 @@ 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 are familiar with Linux-kernel concurrency and the > > use of LKMM, and would like a cheat sheet to remind you > > of LKMM's guarantees: cheatsheet.txt > > @@ -37,12 +49,16 @@ o You are interested in the publications related to LKMM, including > > DESCRIPTION OF FILES > > ==================== > > > > -Documentation/README > > +README > > This file. > > > > Documentation/cheatsheet.txt > > Quick-reference guide to the Linux-kernel memory model. > > > > +Documentation/control-dependencies.txt > > + A guide to preventing compiler optimizations from destroying > > + your control dependencies. > > + > > Documentation/explanation.txt > > Describes the memory model in detail. > [...]
