set the loadMeta log level to debug.

https://github.com/apache/hbase/blob/2444d268901644d90def3fca39505627ff956b40/hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java#L167
test 100w Regions, the log level is info, it takes more than 250 seconds to load metadata. The log is debug. It takes more than 100 seconds to load metadata.