CCAN's htable uses open addressing, and bit stealing from the pointers for maximal density (extra hash bits go here to avoid derefs for misses). The result is

CCAN's htable uses open addressing, and bit stealing from the pointers for maximal density (extra hash bits go here to avoid derefs for misses). The result is that performance tends to be great up to about 95% full. The resize operation is a dumb double-and-rehash, but for most programs, the lower cache impact is a win.