hi all: in buddy allocator heart function, __alloc_pages_nodemask, I found we use zonelist-> _zonerefs to iterate all the zone in NUMA or UMA. My questions are: 1. the advantage of travelling zonelist-> _zonerefs instead of iterating zones on each node is because it is faster, right? 2. zonelist-> _zonerefs has recorded information of each zone, under what circumstances we will iterated zone of node to get zone's data instead of zonelist-> _zonerefs appreciate your help in advance,