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Message-ID: <AANLkTiluIibUglhf28JAeSLzBC0E1Zw0STPoqFTbXcev@mail.gmail.com>
Date: Tue, 8 Jun 2010 16:00:58 -0700
From: Tom Herbert <therbert@...gle.com>
To: Eric Dumazet <eric.dumazet@...il.com>
Cc: John Fastabend <john.r.fastabend@...el.com>,
Stephen Hemminger <shemminger@...tta.com>,
Peter Lieven <pl@....net>,
"davem@...emloft.net" <davem@...emloft.net>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: RFS seems to have incompatiblities with bridged vlans
How about only checking against dev->num_rx_queues when that value is
greater than one. Since bonding device is calling alloc_netdev, it is
not going to set the queue mapping, but dev->num_rx_queues will be one
in that case (this handles any intermediate driver that does do
multiple queues).
diff --git a/net/core/dev.c b/net/core/dev.c
index 6f330ce..30ab66d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2270,7 +2270,7 @@ static int get_rps_cpu(struct net_device *dev,
struct sk_buff *skb,
u16 v16[2];
} ports;
- if (skb_rx_queue_recorded(skb)) {
+ if (skb_rx_queue_recorded(skb) && dev->num_rx_queues > 1) {
u16 index = skb_get_rx_queue(skb);
if (unlikely(index >= dev->num_rx_queues)) {
if (net_ratelimit()) {
On Tue, Jun 8, 2010 at 7:18 AM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> Le lundi 07 juin 2010 à 15:30 -0700, John Fastabend a écrit :
>
>> There is always a possibility that the underlying device sets the
>> queue_mapping to be greater then num_cpus. Also I suspect the same
>> issue exists with bonding devices. Maybe something like the following
>> is worth while? compile tested only,
>>
>> [PATCH] 8021q: vlan reassigns dev without check queue_mapping
>>
>> recv path reassigns skb->dev without sanity checking the
>> queue_mapping field. This can result in the queue_mapping
>> field being set incorrectly if the new dev supports less
>> queues then the underlying device.
>>
>> This patch just resets the queue_mapping to 0 which should
>> resolve this issue? Any thoughts?
>>
>> The same issue could happen on bonding devices as well.
>>
>> Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
>> ---
>>
>> net/8021q/vlan_core.c | 6 ++++++
>> 1 files changed, 6 insertions(+), 0 deletions(-)
>>
>> diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
>> index bd537fc..ad309f8 100644
>> --- a/net/8021q/vlan_core.c
>> +++ b/net/8021q/vlan_core.c
>> @@ -21,6 +21,9 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct
>> vlan_group *grp,
>> if (!skb->dev)
>> goto drop;
>>
>> + if (unlikely(skb->queue_mapping >= skb->dev->real_num_tx_queues))
>> + skb_set_queue_mapping(skb, 0);
>> +
>> return (polling ? netif_receive_skb(skb) : netif_rx(skb));
>>
>> drop:
>> @@ -93,6 +96,9 @@ vlan_gro_common(struct napi_struct *napi, struct
>> vlan_group *grp,
>> if (!skb->dev)
>> goto drop;
>>
>> + if (unlikely(skb->queue_mapping >= skb->dev->real_num_tx_queues))
>> + skb_set_queue_mapping(skb, 0);
>> +
>> for (p = napi->gro_list; p; p = p->next) {
>> NAPI_GRO_CB(p)->same_flow =
>> p->dev == skb->dev && !compare_ether_header(
>> --
>
> Only a workaround, added in hot path in a otherwise 'good' driver
> (multiqueue enabled and ready)
>
> eth0 -------> bond / bridge ---------> vlan.id
> (nbtxq=8) (ntxbq=1) (nbtxq=X)
>
> X is capped to 1 because of bond/bridge, while bond has no "queue"
> (LLTX driver)
>
> Solutions :
>
> 1) queue_mapping could be silently tested in get_rps_cpu()...
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6f330ce..3a3f7f6 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2272,14 +2272,11 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
>
> if (skb_rx_queue_recorded(skb)) {
> u16 index = skb_get_rx_queue(skb);
> - if (unlikely(index >= dev->num_rx_queues)) {
> - if (net_ratelimit()) {
> - pr_warning("%s received packet on queue "
> - "%u, but number of RX queues is %u\n",
> - dev->name, index, dev->num_rx_queues);
> - }
> - goto done;
> - }
> + if (WARN_ONCE(index >= dev->num_rx_queues,
> + KERN_WARNING "%s received packet on queue %u, "
> + "but number of RX queues is %u\n",
> + dev->name, index, dev->num_rx_queues))
> + index %= dev->num_rx_queues;
> rxqueue = dev->_rx + index;
> } else
> rxqueue = dev->_rx;
>
>
>
> 2) bond/bridge should setup more queues, just in case.
> We probably need to be able to make things more dynamic,
> (propagate nbtxq between layers) but not for 2.6.35
>
>
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 5e12462..ce813dd 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -5012,8 +5012,8 @@ int bond_create(struct net *net, const char *name)
>
> rtnl_lock();
>
> - bond_dev = alloc_netdev(sizeof(struct bonding), name ? name : "",
> - bond_setup);
> + bond_dev = alloc_netdev_mq(sizeof(struct bonding), name ? name : "",
> + bond_setup, max(64, nr_cpu_ids));
> if (!bond_dev) {
> pr_err("%s: eek! can't alloc netdev!\n", name);
> rtnl_unlock();
>
>
> --
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