Messages in this thread | | | From | Jianyu Zhan <> | Date | Thu, 25 Feb 2016 14:41:07 +0800 | Subject | Re: [PATCH tip/core/rcu 02/14] documentation: Fix control dependency and identical stores |
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On Thu, Feb 25, 2016 at 5:40 AM, Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: > So ordering between the read from "a" and the write to "b" is still > preserved. The reason this works is that the smp_mb() does all the > ordering, so the fact that the control dependency has been eliminated > is irrelevant.
Thanks, Paul, nice clarification.
I thinks this example qualifies as an good example to demonstrate the subtle scope of effect of these two level barriers.
A vivid example is always better for understanding instead of learning "barrier() is compiler-level barrier, and smp_*mb() is processor-level barrier" by rote , especially for the new comers to memory-barriers.txt. ;-)
Thanks, Jianyu Zhan
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