svn commit: r284888 - stable/10/share/man/man9
Konstantin Belousov
kib at FreeBSD.org
Sat Jun 27 09:47:29 UTC 2015
Author: kib
Date: Sat Jun 27 09:47:28 2015
New Revision: 284888
URL: https://svnweb.freebsd.org/changeset/base/284888
Log:
MFC r284646:
The barriers, provided by _acq and _rel atomics, are acquire and
release barriers, not read and write barriers.
Modified:
stable/10/share/man/man9/atomic.9
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/share/man/man9/atomic.9
==============================================================================
--- stable/10/share/man/man9/atomic.9 Sat Jun 27 09:44:14 2015 (r284887)
+++ stable/10/share/man/man9/atomic.9 Sat Jun 27 09:47:28 2015 (r284888)
@@ -23,7 +23,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd August 20, 2013
+.Dd June 20, 2015
.Dt ATOMIC 9
.Os
.Sh NAME
@@ -123,7 +123,9 @@ The first form just performs the operati
The second form uses a read memory barrier, and the third variant uses a write
memory barrier.
.Pp
-The second variant of each operation includes a read memory barrier.
+The second variant of each operation includes an
+.Em acquire
+memory barrier.
This barrier ensures that the effects of this operation are completed before the
effects of any later data accesses.
As a result, the operation is said to have acquire semantics as it acquires a
@@ -137,7 +139,9 @@ For example, to subtract two integers en
happen after the subtraction is performed, use
.Fn atomic_subtract_acq_int .
.Pp
-The third variant of each operation includes a write memory barrier.
+The third variant of each operation includes a
+.Em release
+memory barrier.
This ensures that all effects of all previous data accesses are completed
before this operation takes place.
As a result, the operation is said to have release semantics as it releases
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