Multiple processes listing a large directory over nfs concurrently takes a very long time

Issue

• When multiple processes are listing the contents of a directory simultaneously, calls to getdents() can take a very long time. This occurs even if the contents of the directory are unchanging.
• As the number of directory entries increases, and as the number of processes listing the directory concurrently increases, the time required to list a directory can become huge.
• This issue is different than https://access.redhat.com/solutions/2249321 due to the fact that the directory being listed is not being modified at the same time it is being listed.