bitkeeper revision 1.1159.223.68 (4204a5090n9Cd2ll6YcdL3tK2uDu1A)

bitkeeper revision 1.1159.223.68 (4204a5090n9Cd2ll6YcdL3tK2uDu1A)

Bug fix to the scheduler for writable page tables.
Don't flush the writable page tables inside __enter_scheduler()
until after we've committed to switching to another domain.

Here's the problem: if enough debugging messages are enabled (for
example, shadow mode and/or writable page tables messages), then we
can get into a situation where we *always* visit
__enter_scheduler() after every page fault and/or hypercall.  If we
flush the writable page tables every time we take a page fault,
we'll never end up actually getting into the domain with write
permissions enabled to its page table.

Signed-off-by: michael.fetterman@cl.cam.ac.uk