From: Ding Tianhong <dingtianhong@huawei•com>
To: Nikolay Aleksandrov <nikolay@redhat•com>
Cc: Jay Vosburgh <fubar@us•ibm.com>,
Andy Gospodarek <andy@greyhouse•net>,
"David S. Miller" <davem@davemloft•net>,
Veaceslav Falico <vfalico@redhat•com>,
Netdev <netdev@vger•kernel.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6•org>
Subject: Re: [PATCH net-next 6/6] bonding: use RCU protection for alb xmit path
Date: Wed, 4 Sep 2013 14:24:47 +0800 [thread overview]
Message-ID: <5226D22F.2060706@huawei.com> (raw)
In-Reply-To: <5225B855.6080101@redhat.com>
On 2013/9/3 18:22, Nikolay Aleksandrov wrote:
> On 08/30/2013 12:05 PM, Ding Tianhong wrote:
>> The commit 278b20837511776dc9d5f6ee1c7fabd5479838bb
>> (bonding: initial RCU conversion) has convert the roundrobin, active-backup,
>> broadcast and xor xmit path to rcu protection, the performance will be better
>> for these mode, so this time, convert xmit path for alb mode.
>>
>> Suggested-by: Nikolay Aleksandrov <nikolay@redhat•com>
>> Signed-off-by: Ding Tianhong <dingtianhong@huawei•com>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei•com>
>> Cc: Nikolay Aleksandrov <nikolay@redhat•com>
>> Cc: Veaceslav Falico <vfalico@redhat•com>
>> ---
>> drivers/net/bonding/bond_alb.c | 20 +++++++++-----------
>> drivers/net/bonding/bonding.h | 2 +-
>> 2 files changed, 10 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>> index d266c56..e94a5d0 100644
>> --- a/drivers/net/bonding/bond_alb.c
>> +++ b/drivers/net/bonding/bond_alb.c
>> @@ -229,7 +229,7 @@ static struct slave *tlb_get_least_loaded_slave(struct bonding *bond)
>> max_gap = LLONG_MIN;
>>
>> /* Find the slave with the largest gap */
>> - bond_for_each_slave(bond, slave) {
>> + bond_for_each_slave_rcu(bond, slave) {
>> if (SLAVE_IS_OK(slave)) {
>> long long gap = compute_gap(slave);
>>
>> @@ -625,10 +625,12 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
>> {
>> struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
>> struct arp_pkt *arp = arp_pkt(skb);
>> - struct slave *assigned_slave;
>> + struct slave *assigned_slave, *curr_active_slave;
>> struct rlb_client_info *client_info;
>> u32 hash_index = 0;
>>
>> + curr_active_slave = rcu_dereference(bond->curr_active_slave);
>> +
> I think this code is prone to a race condition with the slave removal, because
> without the lock __bond_release_one() may think that it has done the LB release
> (bond_alb_deinit_slave) and cleared the slave while you may set it after locking.
> I guess you should move the dereference after the lock so to make sure that the
> LB release hasn't passed (or it has and it'll be different).
>
yes, I ignore it, fix it in next version.
>> _lock_rx_hashtbl(bond);
>>
>> hash_index = _simple_hash((u8 *)&arp->ip_dst, sizeof(arp->ip_dst));
>> @@ -654,9 +656,9 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
>> * move the old client to primary (curr_active_slave) so
>> * that the new client can be assigned to this entry.
>> */
>> - if (bond->curr_active_slave &&
>> - client_info->slave != bond->curr_active_slave) {
>> - client_info->slave = bond->curr_active_slave;
>> + if (curr_active_slave &&
>> + client_info->slave != curr_active_slave) {
>> + client_info->slave = curr_active_slave;
>> rlb_update_client(client_info);
>> }
>> }
>> @@ -1336,8 +1338,6 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
>>
>> /* make sure that the curr_active_slave do not change during tx
>> */
>> - read_lock(&bond->lock);
>> - read_lock(&bond->curr_slave_lock);
>>
>> switch (ntohs(skb->protocol)) {
>> case ETH_P_IP: {
>> @@ -1420,12 +1420,12 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
>>
>> if (!tx_slave) {
>> /* unbalanced or unassigned, send through primary */
>> - tx_slave = bond->curr_active_slave;
>> + tx_slave = rcu_dereference(bond->curr_active_slave);
>> bond_info->unbalanced_load += skb->len;
>> }
>>
>> if (tx_slave && SLAVE_IS_OK(tx_slave)) {
>> - if (tx_slave != bond->curr_active_slave) {
>> + if (tx_slave != rcu_dereference(bond->curr_active_slave)) {
>> memcpy(eth_data->h_source,
>> tx_slave->dev->dev_addr,
>> ETH_ALEN);
>> @@ -1440,8 +1440,6 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
>> }
>> }
>>
>> - read_unlock(&bond->curr_slave_lock);
>> - read_unlock(&bond->lock);
>> if (res) {
>> /* no suitable interface, frame not sent */
>> kfree_skb(skb);
>> diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
>> index a3ab47f..9bc3af0 100644
>> --- a/drivers/net/bonding/bonding.h
>> +++ b/drivers/net/bonding/bonding.h
>> @@ -536,7 +536,7 @@ static inline struct slave *bond_slave_has_mac(struct bonding *bond,
>> {
>> struct slave *tmp;
>>
>> - bond_for_each_slave(bond, tmp)
>> + bond_for_each_slave_rcu(bond, tmp)
>> if (ether_addr_equal_64bits(mac, tmp->dev->dev_addr))
>> return tmp;
>>
>>
>
>
> .
>
prev parent reply other threads:[~2013-09-04 6:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-30 10:05 [PATCH net-next 6/6] bonding: use RCU protection for alb xmit path Ding Tianhong
2013-09-03 10:22 ` Nikolay Aleksandrov
2013-09-04 6:24 ` Ding Tianhong [this message]
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