CACHE_STRUCT_LEN
(roundup2(CACHE_STRUCT_LEN(CACHE_PATH_CUTOFF_MIN), \
_Alignof(struct namecache_ts)) - CACHE_STRUCT_LEN(0))
CACHE_STRUCT_LEN(CACHE_PATH_CUTOFF)
roundup2(CACHE_STRUCT_LEN(NAME_MAX), _Alignof(struct namecache_ts))