+
+ Snapshot, // The mapped object will also be made CopyOnWrite, so
+ // that any writes to the mapped page via any mapping
+ // will cause a fault. Thus, after the snapshot, the
+ // only changes that will be visible will be through
+ // the new mapping. This is ideal for things like fork()
+ // and file versioning, and is used by AddrSpace.clone().
+ //
+ // If not set, then only the new mapping will be
+ // CopyOnWrite, so if another mapping updates the page
+ // before a write occurs through this mapping (thus
+ // breaking CopyOnWrite), the change will be visible in
+ // the new mapping. This is ideal for private
+ // mappings, where all that is desired is that the new
+ // mapping cannot change the underlying object (while
+ // keeping the mapping writeable).
+ //
+ // Ignored if CopyOnWrite is not set.
+