From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: Re: [PATCH net-next v2 3/10] bonding: rebuild the lock use for bond_alb_monitor() Date: Fri, 08 Nov 2013 17:07:30 +0100 Message-ID: <527D0C42.3010402@redhat.com> References: <527C4778.5080209@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Jay Vosburgh , Andy Gospodarek , "David S. Miller" , Veaceslav Falico , Netdev To: Ding Tianhong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49876 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756350Ab3KHQKz (ORCPT ); Fri, 8 Nov 2013 11:10:55 -0500 In-Reply-To: <527C4778.5080209@huawei.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/08/2013 03:07 AM, Ding Tianhong wrote: > The bond_alb_monitor use bond lock to protect the bond slave list, > it is no effect here, we need to use RTNL or RCU to replace bond lock, > the bond_alb_monitor will called 10 times one second, RTNL may loss > performance here, so the bond lock replace with RCU to protect the > bond slave list, also the RTNL is preserved, the logic of the monitor > did not changed. > > Suggested-by: Jay Vosburgh > Suggested-by: Veaceslav Falico > Signed-off-by: Ding Tianhong > --- > drivers/net/bonding/bond_alb.c | 21 +++++++++------------ > 1 file changed, 9 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c > index 1fae915..ffdb91b 100644 > --- a/drivers/net/bonding/bond_alb.c > +++ b/drivers/net/bonding/bond_alb.c > @@ -816,7 +816,7 @@ static void rlb_rebalance(struct bonding *bond) > for (; hash_index != RLB_NULL_INDEX; > hash_index = client_info->used_next) { > client_info = &(bond_info->rx_hashtbl[hash_index]); > - assigned_slave = rlb_next_rx_slave(bond); > + assigned_slave = __rlb_next_rx_slave(bond); > if (assigned_slave && (client_info->slave != assigned_slave)) { > client_info->slave = assigned_slave; > client_info->ntt = 1; > @@ -1495,9 +1495,10 @@ void bond_alb_monitor(struct work_struct *work) > struct list_head *iter; > struct slave *slave; > > - read_lock(&bond->lock); > + rcu_read_lock(); > > - if (!bond_has_slaves(bond)) { > + if (!bond_has_slaves_rcu(bond)) { > + rcu_read_unlock(); > bond_info->tx_rebalance_counter = 0; > bond_info->lp_counter = 0; > goto re_arm; If I'm not mistaken there's one more bond_for_each_slave() inside this function which should be converted to RCU. > @@ -1528,7 +1529,7 @@ void bond_alb_monitor(struct work_struct *work) > > read_lock(&bond->curr_slave_lock); > > - bond_for_each_slave(bond, slave, iter) { > + bond_for_each_slave_rcu(bond, slave, iter) { > tlb_clear_slave(bond, slave, 1); > if (slave == bond->curr_active_slave) { > SLAVE_TLB_INFO(slave).load = > @@ -1552,11 +1553,9 @@ void bond_alb_monitor(struct work_struct *work) > * dev_set_promiscuity requires rtnl and > * nothing else. Avoid race with bond_close. > */ > - read_unlock(&bond->lock); > - if (!rtnl_trylock()) { > - read_lock(&bond->lock); > + rcu_read_unlock(); > + if (!rtnl_trylock()) > goto re_arm; > - } > > bond_info->rlb_promisc_timeout_counter = 0; > > @@ -1568,7 +1567,7 @@ void bond_alb_monitor(struct work_struct *work) > bond_info->primary_is_promisc = 0; > > rtnl_unlock(); > - read_lock(&bond->lock); > + rcu_read_lock(); > } > > if (bond_info->rlb_rebalance) { > @@ -1590,11 +1589,9 @@ void bond_alb_monitor(struct work_struct *work) > } > } > } > - > + rcu_read_unlock(); > re_arm: > queue_delayed_work(bond->wq, &bond->alb_work, alb_delta_in_ticks); > - > - read_unlock(&bond->lock); > } > > /* assumption: called before the slave is attached to the bond >