Re: [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs

[Eric Dumazet <eric dumazet gmail com>]

Le lundi 31 mai 2010 à 19:46 +0200, Andi Kleen a écrit :
> On Mon, May 31, 2010 at 06:34:55PM +0200, Eric Dumazet wrote:
> 
> Yes seems like I'm behind on per cpu innovations.
> 
> > Since commit e0fdb0e050eae331, we have a __percpu annotation so that
> > sparse can be augmented. This would also make the comment unnecessary...
> 
> I think the comment is still necessary.
> 
> > 
> > > +       __get_cpu_var(io_wq_cpu) = current;
> > 
> > 	this_cpu_write(io_wq_cpu, current)
> 
> And this one looks more ugly than before and does not seem
> to generate better code, so I decided to skip it.

This is because you whould use __this_cpu_write() in this context of
course ;)

generated code : one instruction