Commit Graph

2 Commits

Author SHA1 Message Date
Akira Yokosawa
5ef0a07a79 Documentation/litmus-tests: Add note on herd7 7.56 in atomic litmus test
herdtools 7.56 has enhanced herd7's C parser so that the "(void)expr"
construct in Atomic-RMW-ops-are-atomic-WRT-atomic_set.litmus is
accepted.

This is independent of LKMM's cat model, so mention the required
version in the header of the litmus test and its entry in README.

CC: Boqun Feng <boqun.feng@gmail.com>
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Acked-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-29 12:05:18 -07:00
Boqun Feng
4dcd4d36dd Documentation/litmus-tests/atomic: Add a test for atomic_set()
We already use a litmus test in atomic_t.txt to describe the behavior of
an atomic_set() with the an atomic RMW, so add it into atomic-tests
directory to make it easily accessible for anyone who cares about the
semantics of our atomic APIs.

Besides currently the litmus test "atomic-set" in atomic_t.txt has a few
things to be improved:

1)	The CPU/Processor numbers "P1,P2" are not only inconsistent with
	the rest of the document, which uses "CPU0" and "CPU1", but also
	unacceptable by the herd tool, which requires processors start
	at "P0".

2)	The initialization block uses a "atomic_set()", which is OK, but
	it's better to use ATOMIC_INIT() to make clear this is an
	initialization.

3)	The return value of atomic_add_unless() is discarded
	inexplicitly, which is OK for C language, but it will be helpful
	to the herd tool if we use a void cast to make the discard
	explicit.

4)	The name and the paragraph describing the test need to be more
	accurate and aligned with our wording in LKMM.

Therefore fix these in both atomic_t.txt and the new added litmus test.

Acked-by: Andrea Parri <parri.andrea@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-29 12:05:18 -07:00