* Eric Dumazet (eric.dumazet@gmail.com) wrote:
quoted text
> Herbert Xu a écrit :
> > 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,
> 
> +1 :)
> 
> Do you mean using a spinlock instead or what ?
> 

I think he meant RCU.

quoted text
> Also, how many arches are able to have a true __read_lock()
> (or __spin_lock() if that matters), without acquire semantic ?

At least PowerPC, MIPS, recent ARM, alpha.

Mathieu


-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html