On Thu, Nov 05, 2020 at 02:00:14PM -0800, paulmck@xxxxxxxxxx wrote: > From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> > --- > tools/memory-model/Documentation/glossary.txt | 155 ++++++++++++++++++++++++++ > 1 file changed, 155 insertions(+) > create mode 100644 tools/memory-model/Documentation/glossary.txt > > diff --git a/tools/memory-model/Documentation/glossary.txt b/tools/memory-model/Documentation/glossary.txt > new file mode 100644 > index 0000000..036fa28 > --- /dev/null > +++ b/tools/memory-model/Documentation/glossary.txt > @@ -0,0 +1,155 @@ > +This document contains brief definitions of LKMM-related terms. Like most > +glossaries, it is not intended to be read front to back (except perhaps > +as a way of confirming a diagnosis of OCD), but rather to be searched > +for specific terms. > + > + > +Address Dependency: When the address of a later memory access is computed > + based on the value returned by an earlier load, an "address > + dependency" extends from that load extending to the later access. > + Address dependencies are quite common in RCU read-side critical > + sections: > + > + 1 rcu_read_lock(); > + 2 p = rcu_dereference(gp); > + 3 do_something(p->a); > + 4 rcu_read_unlock(); > + > + In this case, because the address of "p->a" on line 3 is computed > + from the value returned by the rcu_dereference() on line 2, the > + address dependency extends from that rcu_dereference() to that > + "p->a". In rare cases, optimizing compilers can destroy address > + dependencies. Please see Documentation/RCU/rcu_dereference.txt > + for more information. > + > + See also "Control Dependency". There should also be an entry for "Data Dependency", linked from here and from Control Dependency. > +Marked Access: An access to a variable that uses an special function or > + macro such as "r1 = READ_ONCE()" or "smp_store_release(&a, 1)". How about "r1 = READ_ONCE(x)"? Alan
