On Thu, Jun 26, 2014 at 6:40 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Andres Freund <and...@2ndquadrant.com> writes: >> On 2014-06-26 14:13:07 -0700, Tom Lane wrote: >>> Surely it had better be a read barrier as well? > >> I don't immediately see why it has to be read barrier? Hoisting a load >> from after the release into the locked area of code should be safe? > > No doubt, but delaying a read till after the unlocking write would > certainly not be safe. > > AFAICT, README.barrier completely fails to define what we think the > semantics of pg_read_barrier and pg_write_barrier actually are, so if > you believe that a write barrier prevents reordering of reads relative to > writes, you'd better propose some new text for that file. It certainly > doesn't say that today.
The relevant text is in barrier.h -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
