This file shows the values in struct dentry_stat_t, as defined in fs/dcache.c::
struct dentry_stat_t dentry_stat { long nr_dentry; long nr_unused; long age_limit; /* age in seconds / long want_pages; / pages requested by system / long nr_negative; / # of unused negative dentries / long dummy; / Reserved for future use */ };
Dentries are dynamically allocated and deallocated.
nr_dentry shows the total number of dentries allocated (active
nr_unused shows the number of dentries that are not actively used, but are saved in the LRU list for future reuse.age_limit is the age in seconds after which dcache entries can be reclaimed when memory is short and want_pages is nonzero when shrink_dcache_pages() has been called and the dcache isn’t pruned yet.
nr_negative shows the number of unused dentries that are also negative dentries which do not map to any files. Instead, they help speeding up rejection of non-existing files provided by the users.