Checking dentry-cache statistics

• To see statistics about the dentry-cache:

       $ cat /proc/sys/fs/dentry-state 
       17782	9733	45	0	0	0
       

• Entries are as follows:
  1. nr_dentry - number of allocated dentries in the cache.
  2. nr_unused - number of unused (=free) entries in the cache.
  3. age_limit - the minimum age (in seconds) for a dentry, until the kernel may reclaim it due to memory pressure.
  4. want_pages - non-zero when the kernel started a shrink dentry-cache operation that was not yet finished.
  5. unused.
  6. unused.

Originally written by guy keren