Re: [RFC v2 1/7] hashtable: introduce a small and naive hashtable

Eric Dumazet
2012-08-03T17:39:10Z

On Fri, 2012-08-03 at 16:23 +0200, Sasha Levin wrote:
> This hashtable implementation is using hlist buckets to provide a simple
> hashtable to prevent it from getting reimplemented all over the kernel.
>

> +static void hash_add(struct hash_table *ht, struct hlist_node *node, long key)
> +{
> + hlist_add_head(node,
> + &ht->buckets[hash_long((unsigned long)key, HASH_BITS(ht))]);
> +}
> +

Why key is a long, casted later to "unsigned long" ?

hash_long() is expensive on 64bit arches, and not really needed
if key is an u32 from the beginning ( I am referring to your patches 6 &
7 using jhash() )

Maybe you could use a macro, so that we can automatically select
hash_32() if key is an u32, and hash_long() for other types.