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Date: Wed, 5 Jun 2024 13:55:08 -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,
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  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 v2] tools/memory-model: Document herd7 (abstract)
 representation
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 <037bc316-3e8c-4748-bade-ffdad4239646@rowland.harvard.edu>
 <ZmCXwjX/Rx7zKWpj@andrea>
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On Wed, Jun 05, 2024 at 06:52:18PM +0200, Andrea Parri wrote:
> > I wonder if we really need a special notation for lk-rmw.  Is anything 
> > wrong with using the normal rmw notation for these links?
> 
> I don't think we need the special notation: in fact, herd7 doesn't know
> anything about these lk-rmw or rmw links between lock events until after
> tools/memory-model/ (the .cat file) has established such links cf.
> 
>   (* Link Lock-Reads to their RMW-partner Lock-Writes *)
>   let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po)
>   let rmw = rmw | lk-rmw
> 
> I was trying to be informative (since that says "lk-rmw is a subrelation
> of rmw) but, in order to be faithful to the scope of this document (herd
> representation), the doc should really just indicate LKR ->po LKW.
> 
> Thoughts?

I agree; be faithful to the document's scope and just say LKR ->po LKW.

Were there other things like this in the table?  I didn't notice any.

Alan