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Date:   Thu, 15 Feb 2018 23:30:09 +0100
From:   Andrea Parri <parri.andrea@gmail.com>
To:     "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc:     linux-kernel@vger.kernel.org, mingo@kernel.org,
        stern@rowland.harvard.edu, will.deacon@arm.com,
        peterz@infradead.org, boqun.feng@gmail.com, npiggin@gmail.com,
        dhowells@redhat.com, j.alglave@ucl.ac.uk, luc.maranget@inria.fr,
        akiyks@gmail.com
Subject: Re: [PATCH RFC tip/lkmm 08/10] EXP Remove understore from
 smp_mb__before_atomic() workings
Message-ID: <20180215223009.GA5460@andrea>
References: <20180209141832.GA17505@linux.vnet.ibm.com>
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On Fri, Feb 09, 2018 at 06:20:29AM -0800, Paul E. McKenney wrote:
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

nit: s/understore/underscore  (a very understandable lapsus, BTW ;-)

According to the cover letter, patches 8-10 of this series are intended
to be squashed together;  it could be useful to add a description then:
the motivation for these changes might appear "trivial" today;  months/
years from now?  mmh, I can't put my finger on it ;-)

IMO,  this descrition should also mention why this solution "is the way
to go" (e.g., compare with the solution recently implemented by Akira).

  Andrea


> ---
>  tools/memory-model/linux-kernel.bell | 2 +-
>  tools/memory-model/linux-kernel.cat  | 2 +-
>  tools/memory-model/linux-kernel.def  | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
> index b984bbda01a5..558bbef9e08a 100644
> --- a/tools/memory-model/linux-kernel.bell
> +++ b/tools/memory-model/linux-kernel.bell
> @@ -28,7 +28,7 @@ enum Barriers = 'wmb (*smp_wmb*) ||
>  		'rcu-lock (*rcu_read_lock*)  ||
>  		'rcu-unlock (*rcu_read_unlock*) ||
>  		'sync-rcu (*synchronize_rcu*) ||
> -		'before_atomic (*smp_mb__before_atomic*) ||
> +		'before-atomic (*smp_mb__before_atomic*) ||
>  		'after_atomic (*smp_mb__after_atomic*) ||
>  		'after_spinlock (*smp_mb__after_spinlock*)
>  instructions F[Barriers]
> diff --git a/tools/memory-model/linux-kernel.cat b/tools/memory-model/linux-kernel.cat
> index babe2b3b0bb3..31c08a44c088 100644
> --- a/tools/memory-model/linux-kernel.cat
> +++ b/tools/memory-model/linux-kernel.cat
> @@ -29,7 +29,7 @@ let rb-dep = [R] ; fencerel(Rb_dep) ; [R]
>  let rmb = [R \ Noreturn] ; fencerel(Rmb) ; [R \ Noreturn]
>  let wmb = [W] ; fencerel(Wmb) ; [W]
>  let mb = ([M] ; fencerel(Mb) ; [M]) |
> -	([M] ; fencerel(Before_atomic) ; [RMW] ; po? ; [M]) |
> +	([M] ; fencerel(Before-atomic) ; [RMW] ; po? ; [M]) |
>  	([M] ; po? ; [RMW] ; fencerel(After_atomic) ; [M]) |
>  	([M] ; po? ; [LKW] ; fencerel(After_spinlock) ; [M])
>  let gp = po ; [Sync-rcu] ; po?
> diff --git a/tools/memory-model/linux-kernel.def b/tools/memory-model/linux-kernel.def
> index a397387f77cc..ff4b756f4a44 100644
> --- a/tools/memory-model/linux-kernel.def
> +++ b/tools/memory-model/linux-kernel.def
> @@ -21,7 +21,7 @@ smp_mb() { __fence{mb} ; }
>  smp_rmb() { __fence{rmb} ; }
>  smp_wmb() { __fence{wmb} ; }
>  smp_read_barrier_depends() { __fence{rb_dep}; }
> -smp_mb__before_atomic() { __fence{before_atomic} ; }
> +smp_mb__before_atomic() { __fence{before-atomic} ; }
>  smp_mb__after_atomic() { __fence{after_atomic} ; }
>  smp_mb__after_spinlock() { __fence{after_spinlock} ; }
>  
> -- 
> 2.5.2
>