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Date: Fri, 24 May 2024 11:53:11 -0400
From: Alan Stern <stern@rowland.harvard.edu>
To: Andrea Parri <parri.andrea@gmail.com>
Cc: 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, hernan.poncedeleon@huaweicloud.com,
  jonas.oberhauser@huaweicloud.com
Subject: Re: [PATCH] tools/memory-model: Document herd7 (internal)
 representation
Message-ID: <1c6d4146-86f8-4fd5-a23e-a95ba2464c9e@rowland.harvard.edu>
References: <20240524151356.236071-1-parri.andrea@gmail.com>
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In-Reply-To: <20240524151356.236071-1-parri.andrea@gmail.com>

On Fri, May 24, 2024 at 05:13:56PM +0200, Andrea Parri wrote:
> tools/memory-model/ and herdtool7 are closely linked: the latter is
> responsible for (pre)processing each C-like macro of a litmus test,
> and for providing the LKMM with a set of events, or "representation",
> corresponding to the given macro.  Provide herd-representation.txt
> to document the representation of synchronization macros, following
> their "classification" in Documentation/atomic_t.txt.
> 
> Suggested-by: Hernan Ponce de Leon <hernan.poncedeleon@huaweicloud.com>
> Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
> ---

> +    |             rcu_dereference | R[once]                                   |
> +    |          rcu_assign_pointer | W[release]                                |
> +    |              srcu_read_lock | R[srcu-lock]                              |
> +    |            srcu_read_unlock | W[srcu-unlock]                            |
> +    |            synchronize_srcu | SRCU[sync-srcu]                           |
> +    ---------------------------------------------------------------------------
> +    |    RMW ops w/o return value |                                           |
> +    ---------------------------------------------------------------------------
> +    |                  atomic_add | R*[noreturn] ->rmw W*[once]               |

What's the difference between R and R*, or between W and W*?

Alan