Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 3/4] Documentation: Memory barrier semantics of atomic_xchg() | Date | Sat, 26 Jan 2013 16:05:19 -0800 |
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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
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