diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 36826c0166c5..fb298e9d6d3a 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -44,6 +44,7 @@ struct rhashtable; * @head_offset: Offset of rhash_head in struct to be hashed * @hash_rnd: Seed to use while hashing * @max_shift: Maximum number of shifts while expanding + * @min_shift: Minimum number of shifts while shrinking * @hashfn: Function to hash key * @obj_hashfn: Function to hash object * @grow_decision: If defined, may return true if table should expand @@ -57,6 +58,7 @@ struct rhashtable_params { size_t head_offset; u32 hash_rnd; size_t max_shift; + size_t min_shift; rht_hashfn_t hashfn; rht_obj_hashfn_t obj_hashfn; bool (*grow_decision)(const struct rhashtable *ht, diff --git a/lib/rhashtable.c b/lib/rhashtable.c index a2c78810ebc1..8dfec3f26d4c 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -298,7 +298,7 @@ int rhashtable_shrink(struct rhashtable *ht, gfp_t flags) ASSERT_RHT_MUTEX(ht); - if (tbl->size <= HASH_MIN_SIZE) + if (ht->shift <= ht->p.min_shift) return 0; ntbl = bucket_table_alloc(tbl->size / 2, flags); @@ -506,9 +506,10 @@ void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash, } EXPORT_SYMBOL_GPL(rhashtable_lookup_compare); -static size_t rounded_hashtable_size(unsigned int nelem) +static size_t rounded_hashtable_size(struct rhashtable_params *params) { - return max(roundup_pow_of_two(nelem * 4 / 3), HASH_MIN_SIZE); + return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), + 1UL << params->min_shift); } /** @@ -566,8 +567,11 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) (!params->key_len && !params->obj_hashfn)) return -EINVAL; + params->min_shift = max_t(size_t, params->min_shift, + ilog2(HASH_MIN_SIZE)); + if (params->nelem_hint) - size = rounded_hashtable_size(params->nelem_hint); + size = rounded_hashtable_size(params); tbl = bucket_table_alloc(size, GFP_KERNEL); if (tbl == NULL)