Re: [PATCH 0/17] MR541: RFC: Shader cache for vkd3d

[Giovanni Mascellani (＠giomasce)]

Giovanni Mascellani (@giomasce) commented about libs/vkd3d/cache.c:
> +{
> - struct vkd3d_cache_object_v1 d;
> - struct rb_entry entry; /* Entry in the hash table. */
> - uint8_t *payload; /* App key + value. Separate allocation to allow eviction. */
>
> +};
> -
>
> +static int vkd3d_shader_cache_compare_key(const void *key, const struct rb_entry *entry)
> +{
> - const uint64_t *k = key;
> - const struct shader_cache_entry *e = RB_ENTRY_VALUE(entry, struct shader_cache_entry, entry);
> -
> - if (*k < e->d.hash)
> -
>    return -1;
> - if (*k > e->d.hash)
> -
>    return 1;
> - return 0;

This only works as far as you keep this "experimental mode" in which you nuke the universe as soon as you find a collision. As soon as you want to fix that, the RB tree comparison function must be aware of the full key as well.