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Date: Mon, 27 May 2024 15:28:00 +0200
From: Andrea Parri <parri.andrea@gmail.com>
To: Hernan Ponce de Leon <hernan.poncedeleon@huaweicloud.com>
Cc: stern@rowland.harvard.edu, 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, paulmck@kernel.org,
	akiyks@gmail.com, dlustig@nvidia.com, joel@joelfernandes.org,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	jonas.oberhauser@huaweicloud.com
Subject: Re: [PATCH] tools/memory-model: Document herd7 (internal)
 representation
Message-ID: <ZlSKYA/Y/daiXzfy@andrea>
References: <20240524151356.236071-1-parri.andrea@gmail.com>
 <1a3c892c-903e-8fd3-24a6-2454c2a55302@huaweicloud.com>
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> > +    |                smp_store_mb | W[once] ->po F[mb]                        |
> 
> I expect this one to be hard-coded in herd7 source code, but I cannot find
> it. Can you give me a pointer?

smp_store_mb() is currently mapped to { __store{once}(X,V); __fence{mb}; } in
the .def file, so it's semantically equivalent to "WRITE_ONCE(); smp_mb();".


> What about spin_unlock?

spin_unlock() is listed among the non-RMW ops/macros in the current table: it
is represented by a single UL or "Unlock" event (a special type of Store event
with (some special) Release semantics).


> I found the extra spaces in the failure case very hard to read. Any
> particular reason why you went with this format?

The extra spaces were simply to convey something like "belong to the previous
row/entry", but I'm open to remove them or other suggestions if preferred.

  Andrea