From: Liping Zhang <[email protected]> Since Commit 64b87639c9cb ("netfilter: conntrack: fix race between nf_conntrack proc read and hash resize") introdue the nf_conntrack_get_ht, so there's no need to check nf_conntrack_generation again and again to get the hash table and hash size.
But keep ____nf_conntrack_find unchanged, because it is performance critical path, increase the overhead of the function call is not so good. Suggested-by: Florian Westphal <[email protected]> Signed-off-by: Liping Zhang <[email protected]> --- V2: remove "inline void" declared to nf_conntrack_get_ht, and keep ____nf_conntrack_find unchanged suggested by Florian. net/netfilter/nf_conntrack_core.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 2d46225..23c6db0 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -801,18 +801,15 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, const struct nf_conntrack_zone *zone; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_head *ct_hash; - unsigned int hash, sequence; + unsigned int hash, hsize; struct hlist_nulls_node *n; struct nf_conn *ct; zone = nf_ct_zone(ignored_conntrack); rcu_read_lock(); - do { - sequence = read_seqcount_begin(&nf_conntrack_generation); - hash = hash_conntrack(net, tuple); - ct_hash = nf_conntrack_hash; - } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); + nf_conntrack_get_ht(&ct_hash, &hsize); + hash = __hash_conntrack(net, tuple, hsize); hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) { ct = nf_ct_tuplehash_to_ctrack(h); @@ -878,14 +875,11 @@ static noinline int early_drop(struct net *net, unsigned int _hash) for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { struct hlist_nulls_head *ct_hash; - unsigned hash, sequence, drops; + unsigned int hash, hsize, drops; rcu_read_lock(); - do { - sequence = read_seqcount_begin(&nf_conntrack_generation); - hash = scale_hash(_hash++); - ct_hash = nf_conntrack_hash; - } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); + nf_conntrack_get_ht(&ct_hash, &hsize); + hash = reciprocal_scale(_hash++, hsize); drops = early_drop_list(net, &ct_hash[hash]); rcu_read_unlock(); -- 2.5.5 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
