Attached is the next version of my shared page tables patch.  It's had a
few bugs fixed which were found by Bill Irwin.  I've also added an
exit-time optimization that eliminates some unnecessary pte unsharing.
This was intended to be in the first patch, but I missed it.

As usual, all useful feedback is welcome.

This patch is against 2.5.41.

Dave McCracken

======================================================================
Dave McCracken          IBM Linux Base Kernel Team      1-512-838-3059
dmccr@us.ibm.com                                        T/L   678-3059