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tools/memory-model: Use cumul-fence instead of fence in ->prop example 

To reduce ambiguity in the more exotic ->prop ordering example, this
commit uses the term cumul-fence instead of the term fence for the two
fences, so that the implict ->rfe on loads/stores to Y are covered by
the description.

Link: https://lore.kernel.org/lkml/20190729121745.GA140682@google.com

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
Joel Fernandes (Google) 2019-07-29 08:36:05 -04:00 committed by Paul E. McKenney
parent 7455cdd1a0
commit 6240973e56
1 changed files with 3 additions and 3 deletions
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6
tools/memory-model/Documentation/explanation.txt
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@ -1302,7 +1302,7 @@ followed by an arbitrary number of cumul-fence links, ending with an
rfe link. You can concoct more exotic examples, containing more than
one fence, although this quickly leads to diminishing returns in terms
of complexity. For instance, here's an example containing a coe link
followed by two fences and an rfe link, utilizing the fact that
followed by two cumul-fences and an rfe link, utilizing the fact that
release fences are A-cumulative:
int x, y, z;
@ -1334,10 +1334,10 @@ If x = 2, r0 = 1, and r2 = 1 after this code runs then there is a prop
link from P0's store to its load. This is because P0's store gets
overwritten by P1's store since x = 2 at the end (a coe link), the
smp_wmb() ensures that P1's store to x propagates to P2 before the
store to y does (the first fence), the store to y propagates to P2
store to y does (the first cumul-fence), the store to y propagates to P2
before P2's load and store execute, P2's smp_store_release()
guarantees that the stores to x and y both propagate to P0 before the
store to z does (the second fence), and P0's load executes after the
store to z does (the second cumul-fence), and P0's load executes after the
store to z has propagated to P0 (an rfe link).
In summary, the fact that the hb relation links memory access events