YARN-4751 adds the getUsedCapacity and getAbsoluteUsedCapacity methods to AbstractCSQueue which is used to display queue usage in UI for branch-2.7 and below. However if there is more than one partition in the cluster, with different dominant resources, then queue usage may not be displayed as expected.
Contrived example: Default partition has <90GB, 10vcores>, and "test" partition has <10GB, 90vcores>. root queue in default partition uses <30GB, 10vcores>. Here we expect queue usage to be 100 since it is using all vcores in default partition. But the displayed usage will be (30GB/100GB)/(90GB/100GB) = 33%.