From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH net-next V6 02/14] bridge: Add vlan filtering infrastructure Date: Sun, 20 Jan 2013 12:59:22 -0500 Message-ID: <50FC307A.5090003@redhat.com> References: <1358360289-23249-1-git-send-email-vyasevic@redhat.com> <1358360289-23249-3-git-send-email-vyasevic@redhat.com> Reply-To: vyasevic@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, bridge@lists.linux-foundation.org, davem@davemloft.net, shemminger@vyatta.com, mst@redhat.com, shmulik.ladkani@gmail.com To: =?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51415 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752371Ab3ATR7a (ORCPT ); Sun, 20 Jan 2013 12:59:30 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 01/17/2013 08:57 PM, Micha=B3 Miros=B3aw wrote: > 2013/1/16 Vlad Yasevich : > [...] >> --- /dev/null >> +++ b/net/bridge/br_vlan.c > [...] >> +struct net_port_vlan *nbp_vlan_find(const struct net_port_vlans *v,= u16 vid) >> +{ >> + struct net_port_vlan *pve; >> + >> + /* Must be done either in rcu critical section or with RTNL = held */ >> + WARN_ON_ONCE(!rcu_read_lock_held() && !rtnl_is_locked()); >> + >> + list_for_each_entry_rcu(pve, &v->vlan_list, list) { >> + if (pve->vid =3D=3D vid) >> + return pve; >> + } >> + >> + return NULL; >> +} > > This looks expensive - it's O(n) with n =3D number of configured VLAN= s on a port. > And this is called for every packet. The bridge already has a hash of= VLAN > structures found by br_vlan_find(). You could add a second bitmap the= re > (eg. ingres_ports[]) and check port's bit instead of walking the list= =2E > You would use a bit more memory (64 bytes minus the removed list-head= ) > per configured VLAN but save some cycles in hot path. > Technically wouldn't even need another bitmap as an existing membership= =20 bitmap would cover this case. I did some profiling and the list is=20 faster for 3 vlans per port. Hash is faster for more then 3 vlans. I can easily switch to hash if that is what others think. -vlad > Best Regards, > Micha=B3 Miros=B3aw >