> Peter Zijlstra wrote:
> > On Wed, 2008-08-20 at 20:50 -0600,
jmerkey@wolfmountaingroup.com wrote:
> >
> >> volatiles left in the code due to the previously stated
> >> (and still present) severe breakage of the GNU compiler with SMP
> >> shared data. most of the barrier() functions are just plain broken
> >> and do not result in proper compiler behavior in this tree.
> >
> > Can you provide explicit detail?
> >
> > By using barrier() the compiler should clobber all its memory and
> > registers therefore forcing a write/reload of the variable.
>
> I hope Jeff didn't try mere barrier()s only. smp_wmb() and smp_rmb()
> are the more relevant barrier variants for mdb, from what I remember
> when I last looked at it.
