Hi, My kernel version is 2.6.32. I have verify that same lock is also used in 3.4.6. there is global spin lock at net/ipv4/netfilter/nf_nat_helper.c static DEFINE_SPINLOCK(nf_nat_seqofs_lock); this is used in following functions: adjust_tcp_sequence(); nf_nat_get_offset(); This lock will reduce performance in case of multicore machines. There is a spin_lock in nf_conn structure itself, which is used by tcp_packet() at net/netfilter/nf_conntrack_proto_tcp.c and other places. So can we replace spin_lock_bh(&nf_nat_seqofs_lock); with spin_lock_bh(&ct->lock); regards rajesh -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html