Date: Fri, 3 Jul 2009 23:29:51 +0800
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: mingo@elte.hu, jolsa@redhat.com, a.p.zijlstra@chello.nl,
       netdev@vger.kernel.org, linux-kernel@vger.kernel.org, fbl@redhat.com,
       nhorman@redhat.com, davem@redhat.com, htejun@gmail.com,
       jarkao2@gmail.com, oleg@redhat.com, davidel@xmailserver.org,
       eric.dumazet@gmail.com, Paul.McKenney@us.ibm.com
Subject: Re: [PATCHv5 2/2] memory barrier: adding smp_mb__after_lock
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Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:
> 
> Why don't we create a read_lock without acquire semantic instead (e.g.
> read_lock_nomb(), or something with a better name like __read_lock()) ?
> On architectures where memory barriers are needed to provide the acquire
> semantic, it would be faster to do :
> 
> __read_lock();
> smp_mb();
> 
> than :
> 
> read_lock(); <- e.g. lwsync + isync or something like that
> smp_mb(); <- full sync.

Hmm, why do we even care when read_lock should just die?

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
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