Re: [PATCH] tools/memory-model: Document herd7 (internal) representation

[Alan Stern]

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@xxxxxxxxxxxxxxx>
> Signed-off-by: Andrea Parri <parri.andrea@xxxxxxxxx>
> ---

> +    |             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