CONNTRACK_LOCKS is divisor when computer array index, if it is power of 2, compiler will optimize modulo operation as bitwise AND, or else modulo will lower performance Suggested-by: Florian Westphal <fw@xxxxxxxxx> Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> --- v1-->v2: do not replace modulo operation with AND, only ensure that CONNTRACK_LOCKS is power of 2 net/netfilter/nf_conntrack_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index e139c256e269..f708c376f225 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -2482,6 +2482,7 @@ int nf_conntrack_init_net(struct net *net) int cpu; BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER); + BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS); atomic_set(&net->ct.count, 0); net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu); -- 2.16.2
