balloon_update_driver_allowance
balloon_release_driver_page
only used on the (obsolete, removed) flip path in netfront
alloc_empty_pages_and_pagevec
free_empty_pages_and_pagevec
only used in backend drivers; can be reintroduced when needed
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>