From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, Richard Braun <rbraun@sceen.net>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 3/4] Documentation: Memory barrier semantics of atomic_xchg()
Date: Sat, 26 Jan 2013 16:05:19 -0800 [thread overview]
Message-ID: <1359245120-2266-3-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1359245120-2266-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: Richard Braun <rbraun@sceen.net>
Add atomic_xchg() to documentation for atomic operations and
memory barriers.
Signed-off-by: Richard Braun <rbraun@sceen.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
Documentation/atomic_ops.txt | 2 ++
Documentation/memory-barriers.txt | 1 +
2 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt
index 27f2b21..d9ca5be 100644
--- a/Documentation/atomic_ops.txt
+++ b/Documentation/atomic_ops.txt
@@ -253,6 +253,8 @@ This performs an atomic exchange operation on the atomic variable v, setting
the given new value. It returns the old value that the atomic variable v had
just before the operation.
+atomic_xchg requires explicit memory barriers around the operation.
+
int atomic_cmpxchg(atomic_t *v, int old, int new);
This performs an atomic compare exchange operation on the atomic value v,
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 3c4e1b3..fa5d8a9 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -1685,6 +1685,7 @@ explicit lock operations, described later). These include:
xchg();
cmpxchg();
+ atomic_xchg();
atomic_cmpxchg();
atomic_inc_return();
atomic_dec_return();
--
1.7.8
next prev parent reply other threads:[~2013-01-27 0:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-27 0:04 [PATCH tip/core/rcu 0/4] v2 Documentation and rcutorture changes for 3.9 Paul E. McKenney
2013-01-27 0:05 ` [PATCH tip/core/rcu 1/4] tracing: Export trace_clock_local() Paul E. McKenney
2013-01-27 0:05 ` [PATCH tip/core/rcu 2/4] rcu: Reduce rcutorture tracing Paul E. McKenney
2013-01-27 0:05 ` Paul E. McKenney [this message]
2013-01-27 0:05 ` [PATCH tip/core/rcu 4/4] rcu: Make rcutorture's shuffler task shuffle recently added tasks Paul E. McKenney
2013-01-27 10:47 ` Josh Triplett
2013-01-29 6:40 ` Paul E. McKenney
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