From: Paul E. McKenney Date: Thu, 19 Jun 2014 17:01:23 +0000 (-0700) Subject: documentation: Add acquire/release barriers to pairing rules X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3aa82352681370a6d0a2b2e47a08cd113a1196cc;p=karo-tx-linux.git documentation: Add acquire/release barriers to pairing rules 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 Signed-off-by: Paul E. McKenney Reviewed-by: Tejun Heo --- 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 =============== ===============