Re: memory barrier question

From: Paul E. McKenney
Date: Wed Sep 22 2010 - 14:41:59 EST


On Tue, Sep 21, 2010 at 07:59:10AM -0700, Paul E. McKenney wrote:
> On Mon, Sep 20, 2010 at 01:40:55PM -0700, Paul E. McKenney wrote:
> > On Tue, Sep 21, 2010 at 08:26:14AM +1200, Michael Cree wrote:
> > > On 21/09/10 06:25, Paul E. McKenney wrote:
> > > >But do we really care about Alpha anymore? (I can see it now... The
> > > >Alpha portion of the kernel tree moves to staging...)
> > >
> > > I do.
> > >
> > > Sent from my Compaq Alpha XP1000 :-)
> >
> > In that case, an smp_read_barrier_depends() or rcu_dereference() is
> > also required...
>
> Wait a minute... I finally got a chance to look up the system. This
> system has only a single Alpha CPU, right?
>
> If so, just build a UP kernel and be happy. No need to worry about
> any of these SMP issues.
>
> So, an alternative proposal -- support only UP kernels on Alpha. ;-)

And there do seem to be some SMP Alpha systems still in use:

http://www.alphalinux.org/wiki/index.php/User:Armin76/HW_list

Thanx, Paul
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