From patchwork Sun Mar 15 10:44:36 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herbert Xu X-Patchwork-Id: 450264 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id C6C7D1400B6 for ; Sun, 15 Mar 2015 21:44:47 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752532AbbCOKom (ORCPT ); Sun, 15 Mar 2015 06:44:42 -0400 Received: from ringil.hengli.com.au ([178.18.16.133]:35101 "EHLO ringil.hengli.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752491AbbCOKol (ORCPT ); Sun, 15 Mar 2015 06:44:41 -0400 Received: from gondolin.me.apana.org.au ([192.168.0.6]) by norbury.hengli.com.au with esmtp (Exim 4.80 #3 (Debian)) id 1YX629-0004G0-0S; Sun, 15 Mar 2015 21:44:37 +1100 Received: from herbert by gondolin.me.apana.org.au with local (Exim 4.80) (envelope-from ) id 1YX628-0005oy-PO; Sun, 15 Mar 2015 21:44:36 +1100 Subject: [v1 PATCH 11/14] rhashtable: Allow hashfn to be unset References: <20150315104306.GA21999@gondor.apana.org.au> To: David Miller , tgraf@suug.ch, netdev@vger.kernel.org, Eric Dumazet Message-Id: From: Herbert Xu Date: Sun, 15 Mar 2015 21:44:36 +1100 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Since every current rhashtable user uses jhash as their hash function, the fact that jhash is an inline function causes each user to generate a copy of its code. This function provides a solution to this problem by allowing hashfn to be unset. In which case rhashtable will automatically set it to jhash. Furthermore, if the key length is a multiple of 4, we will switch over to jhash2. Signed-off-by: Herbert Xu --- include/linux/rhashtable.h | 2 ++ lib/rhashtable.c | 19 +++++++++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 00fe294..295580e 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -110,6 +110,7 @@ struct rhashtable_params { * struct rhashtable - Hash table handle * @tbl: Bucket table * @nelems: Number of elements in table + * @key_len: Key length for hashfn * @p: Configuration parameters * @run_work: Deferred worker to expand/shrink asynchronously * @mutex: Mutex to protect current/future table swapping @@ -119,6 +120,7 @@ struct rhashtable { struct bucket_table __rcu *tbl; atomic_t nelems; bool being_destroyed; + unsigned int hashfn_key_len; struct rhashtable_params p; struct work_struct run_work; struct mutex mutex; diff --git a/lib/rhashtable.c b/lib/rhashtable.c index e33e7b9..a2dc855 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -67,7 +67,7 @@ static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash) static u32 key_hashfn(struct rhashtable *ht, const struct bucket_table *tbl, const void *key) { - return rht_bucket_index(tbl, ht->p.hashfn(key, ht->p.key_len, + return rht_bucket_index(tbl, ht->p.hashfn(key, ht->hashfn_key_len, tbl->hash_rnd)); } @@ -858,6 +858,11 @@ static size_t rounded_hashtable_size(struct rhashtable_params *params) (unsigned long)params->min_size); } +static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) +{ + return jhash2(key, length, seed); +} + /** * rhashtable_init - initialize a new hash table * @ht: hash table to be initialized @@ -908,7 +913,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) size = HASH_DEFAULT_SIZE; - if (!params->hashfn || !params->key_len || + if (!params->key_len || (params->obj_hashfn && !params->obj_cmpfn)) return -EINVAL; @@ -924,6 +929,16 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) mutex_init(&ht->mutex); memcpy(&ht->p, params, sizeof(*params)); + ht->hashfn_key_len = ht->p.key_len; + if (!params->hashfn) { + ht->p.hashfn = jhash; + + if (!(ht->hashfn_key_len & (sizeof(u32) - 1))) { + ht->hashfn_key_len /= sizeof(u32); + ht->p.hashfn = rhashtable_jhash2; + } + } + if (params->locks_mul) ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); else