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Subject[tip:locking/core] tools/memory-model: Flag "cumulativity" and "propagation" tests
Commit-ID:  1bd3742043fa44dd0ec25770abdcdfe1f6e8681e
Gitweb: https://git.kernel.org/tip/1bd3742043fa44dd0ec25770abdcdfe1f6e8681e
Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
AuthorDate: Mon, 14 May 2018 16:33:49 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 15 May 2018 08:11:17 +0200

tools/memory-model: Flag "cumulativity" and "propagation" tests

This commit flags WRC+pooncerelease+rmbonceonce+Once.litmus
as being forbidden by smp_store_release() A-cumulativity and
IRIW+mbonceonces+OnceOnce.litmus as being forbidden by the LKMM
propagation rule.

Suggested-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
[ paulmck: Updated wording as suggested by Alan Stern. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/1526340837-12222-11-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/memory-model/litmus-tests/IRIW+mbonceonces+OnceOnce.litmus | 2 +-
tools/memory-model/litmus-tests/README | 9 ++++++---
.../litmus-tests/WRC+pooncerelease+rmbonceonce+Once.litmus | 4 +++-
3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/tools/memory-model/litmus-tests/IRIW+mbonceonces+OnceOnce.litmus b/tools/memory-model/litmus-tests/IRIW+mbonceonces+OnceOnce.litmus
index 50d5db9ea983..98a3716efa37 100644
--- a/tools/memory-model/litmus-tests/IRIW+mbonceonces+OnceOnce.litmus
+++ b/tools/memory-model/litmus-tests/IRIW+mbonceonces+OnceOnce.litmus
@@ -7,7 +7,7 @@ C IRIW+mbonceonces+OnceOnce
* between each pairs of reads. In other words, is smp_mb() sufficient to
* cause two different reading processes to agree on the order of a pair
* of writes, where each write is to a different variable by a different
- * process?
+ * process? This litmus test exercises LKMM's "propagation" rule.
*)

{}
diff --git a/tools/memory-model/litmus-tests/README b/tools/memory-model/litmus-tests/README
index 6919909bbd0f..17eb9a8c222d 100644
--- a/tools/memory-model/litmus-tests/README
+++ b/tools/memory-model/litmus-tests/README
@@ -23,7 +23,8 @@ IRIW+mbonceonces+OnceOnce.litmus
between each pairs of reads. In other words, is smp_mb()
sufficient to cause two different reading processes to agree on
the order of a pair of writes, where each write is to a different
- variable by a different process?
+ variable by a different process? This litmus test is forbidden
+ by LKMM's propagation rule.

IRIW+poonceonces+OnceOnce.litmus
Test of independent reads from independent writes with nothing
@@ -119,8 +120,10 @@ S+wmbonceonce+poacquireonce.litmus

WRC+poonceonces+Once.litmus
WRC+pooncerelease+rmbonceonce+Once.litmus
- These two are members of an extension of the MP litmus-test class
- in which the first write is moved to a separate process.
+ These two are members of an extension of the MP litmus-test
+ class in which the first write is moved to a separate process.
+ The second is forbidden because smp_store_release() is
+ A-cumulative in LKMM.

Z6.0+pooncelock+pooncelock+pombonce.litmus
Is the ordering provided by a spin_unlock() and a subsequent
diff --git a/tools/memory-model/litmus-tests/WRC+pooncerelease+rmbonceonce+Once.litmus b/tools/memory-model/litmus-tests/WRC+pooncerelease+rmbonceonce+Once.litmus
index 97fcbffde9a0..ad3448b941e6 100644
--- a/tools/memory-model/litmus-tests/WRC+pooncerelease+rmbonceonce+Once.litmus
+++ b/tools/memory-model/litmus-tests/WRC+pooncerelease+rmbonceonce+Once.litmus
@@ -5,7 +5,9 @@ C WRC+pooncerelease+rmbonceonce+Once
*
* This litmus test is an extension of the message-passing pattern, where
* the first write is moved to a separate process. Because it features
- * a release and a read memory barrier, it should be forbidden.
+ * a release and a read memory barrier, it should be forbidden. More
+ * specifically, this litmus test is forbidden because smp_store_release()
+ * is A-cumulative in LKMM.
*)

{}
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