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Subject[PATCH tip/core/rcu 3/4] documentation: Add acquire/release barriers to pairing rules
Date
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

It is possible to pair acquire and release barriers with other barriers,
so this commit adds them to the list in the SMP barrier pairing section.

Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
---
Documentation/memory-barriers.txt | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index a6ca533a73fc..2a7c3c4fb53f 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -757,10 +757,12 @@ SMP BARRIER PAIRING
When dealing with CPU-CPU interactions, certain types of memory barrier should
always be paired. A lack of appropriate pairing is almost certainly an error.

-A write barrier should always be paired with a data dependency barrier or read
-barrier, though a general barrier would also be viable. Similarly a read
-barrier or a data dependency barrier should always be paired with at least an
-write barrier, though, again, a general barrier is viable:
+A write barrier should always be paired with a data dependency barrier,
+acquire barrier, release barrier, or read barrier, though a general
+barrier would also be viable. Similarly a read barrier or a data
+dependency barrier should always be paired with at least a write barrier,
+an acquire barrier, or a release barrier, though, again, a general
+barrier is viable:

CPU 1 CPU 2
=============== ===============
--
1.8.1.5


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