Re: SMP/cc Cluster description

[Larry McVoy]

On Thu, Dec 06, 2001 at 08:42:05PM +0100, Daniel Phillips wrote:
> On December 6, 2001 09:02 am, Larry McVoy wrote:
> > On Wed, Dec 05, 2001 at 11:56:17PM -0800, David S. Miller wrote:
> > > These lockless algorithms, instructions like CAS, DCAS, "infinite
> > > consensus number", it's all crap.  You have to seperate out the access
> > > areas amongst different cpus so they don't collide, and none of these
> > > mechanisms do that.
> > 
> > Err, Dave, that's *exactly* the point of the ccCluster stuff.  You get
> > all that seperation for every data structure for free.  Think about
> > it a bit.  Aren't you going to feel a little bit stupid if you do all
> > this work, one object at a time, and someone can come along and do the
> > whole OS in one swoop?  Yeah, I'm spouting crap, it isn't that easy,
> > but it is much easier than the route you are taking.  
> 
> What I don't get after looking at your material, is how you intend to do the 
> locking.  Sharing a mmap across OS instances is fine, but how do processes on 
> the two different OS's avoid stepping on each other when they access the same 
> file?

Exactly the same way they would if they were two processes on a traditional
SMP OS.