hash_key(9)

🌸 NAME 🌸

Okay so this page is hash_key(9) — the little helper that calculates a 64-bit non-cryptographic hash value for the provided 64-bit integer key. That's the whole vibe, bestie. 💖

✨ SYNOPSIS ✨

The signature is giving short and sweet:

u64 hash_key (u64 key );

🎀 ARGUMENTS 🎀

• key — the mapping key. That's it. That's the argument. Lowkey simple, highkey essential. 💅

🦋 DESCRIPTION 🦋

Okay so the implementation is based on Google's CityHash, but it only handles the specific case of an 8-byte input. No cap — that's the exact case this page covers. 🦋

💖 RETURN 💖

It returns the hash of the mapping key. Slay. ✨

👑 SEE ALSO 👑

The kernel file to peek at is ./drivers/md/dm-vdo/int-map.c, plus all these lovely references:

• Introduction(9)
• struct bucket(9)
• struct int_map(9)
• mix(9)
• allocate_buckets(9)
• vdo_int_map_create(9)
• vdo_int_map_free(9)
• vdo_int_map_size(9)
• dereference_hop(9)
• insert_in_hop_list(9)
• select_bucket(9)
• search_hop_list(9)
• vdo_int_map_get(9)
• resize_buckets(9)
• find_empty_bucket(9)
• move_empty_bucket(9)
• update_mapping(9)
• find_or_make_vacancy(9)
• vdo_int_map_put(9)
• vdo_int_map_remove(9)

Sign-off tea: source/version ./drivers/md/dm-vdo, dated October 2026, manual hash_key(9) — bye bestie, go hash something cute! 💅✨