From: paulmck@kernel.org
To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
kernel-team@fb.com, mingo@kernel.org
Cc: stern@rowland.harvard.edu, parri.andrea@gmail.com,
will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com,
npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk,
luc.maranget@inria.fr, akiyks@gmail.com,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 06/14] tools/memory-model: Add an exception for limitations on _unless() family
Date: Mon, 22 Jun 2020 17:52:23 -0700 [thread overview]
Message-ID: <20200623005231.27712-6-paulmck@kernel.org> (raw)
In-Reply-To: <20200623005152.GA27459@paulmck-ThinkPad-P72>
From: Boqun Feng <boqun.feng@gmail.com>
According to Luc, atomic_add_unless() is directly provided by herd7,
therefore it can be used in litmus tests. So change the limitation
section in README to unlimit the use of atomic_add_unless().
Cc: Luc Maranget <luc.maranget@inria.fr>
Acked-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
tools/memory-model/README | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/tools/memory-model/README b/tools/memory-model/README
index fc07b52..b9c562e 100644
--- a/tools/memory-model/README
+++ b/tools/memory-model/README
@@ -207,11 +207,15 @@ The Linux-kernel memory model (LKMM) has the following limitations:
case as a store release.
b. The "unless" RMW operations are not currently modeled:
- atomic_long_add_unless(), atomic_add_unless(),
- atomic_inc_unless_negative(), and
- atomic_dec_unless_positive(). These can be emulated
+ atomic_long_add_unless(), atomic_inc_unless_negative(),
+ and atomic_dec_unless_positive(). These can be emulated
in litmus tests, for example, by using atomic_cmpxchg().
+ One exception of this limitation is atomic_add_unless(),
+ which is provided directly by herd7 (so no corresponding
+ definition in linux-kernel.def). atomic_add_unless() is
+ modeled by herd7 therefore it can be used in litmus tests.
+
c. The call_rcu() function is not modeled. It can be
emulated in litmus tests by adding another process that
invokes synchronize_rcu() and the body of the callback
--
2.9.5
next prev parent reply other threads:[~2020-06-23 0:52 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 0:51 [PATCH memory-model 0/14] LKMM updates for v5.9 Paul E. McKenney
2020-06-23 0:52 ` [PATCH tip/core/rcu 01/14] tools/memory-model: Add recent references paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 02/14] tools/memory-model: Fix "conflict" definition paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 03/14] Documentation: LKMM: Add litmus test for RCU GP guarantee where updater frees object paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 04/14] Documentation: LKMM: Add litmus test for RCU GP guarantee where reader stores paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 05/14] MAINTAINERS: Update maintainers for new Documentation/litmus-tests paulmck
2020-06-23 0:52 ` paulmck [this message]
2020-06-23 0:52 ` [PATCH tip/core/rcu 07/14] Documentation/litmus-tests: Introduce atomic directory paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 08/14] Documentation/litmus-tests/atomic: Add a test for atomic_set() paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 09/14] Documentation/litmus-tests/atomic: Add a test for smp_mb__after_atomic() paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 10/14] tools/memory-model: Fix reference to litmus test in recipes.txt paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 11/14] Documentation/litmus-tests: Merge atomic's README into top-level one paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 12/14] Documentation/litmus-tests: Cite an RCU litmus test paulmck
2020-06-23 0:52 ` [PATCH tip/core/rcu 13/14] tools/memory-model/README: Expand dependency of klitmus7 paulmck
2020-06-23 14:37 ` Akira Yokosawa
2020-06-23 15:54 ` Paul E. McKenney
2020-06-23 22:06 ` [PATCH 1/2] tools/memory-model/README: Mention herdtools7 7.56 in compatibility table Akira Yokosawa
2020-06-23 22:09 ` [PATCH 2/2] Documentation/litmus-tests: Add note on herd7 7.56 in atomic litmus test Akira Yokosawa
2020-06-23 23:24 ` Andrea Parri
2020-06-24 4:05 ` Paul E. McKenney
2020-06-23 22:57 ` [PATCH 1/2] tools/memory-model/README: Mention herdtools7 7.56 in compatibility table Andrea Parri
2020-06-23 0:52 ` [PATCH tip/core/rcu 14/14] docs: fix references for DMA*.txt files paulmck
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