Previously we had a fallback implementation that made a harmless system
call, based on the assumption that system calls must contain a memory
barrier. That shouldn't be reached on any current system, and it seems
highly likely that we can easily find out how to request explicit memory
barriers, if we've already had to find out how to do atomics on a
hypothetical new system.
Removed comments and a function name referred to a spinlock used for
fallback memory barriers, but that changed in 1b468a13, which left some
misleading words behind in a few places.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Suggested-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/721bf39a-ed8a-44b0-8b8e-be3bd81db748%40technowledgy.de
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us
This directory contains the source code distribution of the PostgreSQL
database management system.
PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
Thomas Munro
83aadbeb96