The per-domain partpop queue is locked by the combination of the
per-domain lock and individual reservation mutexes.
vm_reserv_reclaim_contig() scans the queue looking for partially
populated reservations that can be reclaimed in order to satisfy the
During the scan, we drop the per-domain lock. At this point, the rvn
pointer may be invalidated. Take care to load rvn after re-acquiring
the per-domain lock.