* [PATCH] net: fix multiqueue selection
@ 2013-09-07 19:02 Eric Dumazet
2013-09-08 4:08 ` Alexander Duyck
0 siblings, 1 reply; 3+ messages in thread
From: Eric Dumazet @ 2013-09-07 19:02 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Alexander Duyck
From: Eric Dumazet <edumazet@google.com>
commit 416186fbf8c5b4e4465 ("net: Split core bits of netdev_pick_tx
into __netdev_pick_tx") added a bug that disables caching of queue
index in the socket.
This is the source of packet reorders for TCP flows, and
again this is happening more often when using FQ pacing.
Old code was doing
if (queue_index != old_index)
sk_tx_queue_set(sk, queue_index);
Alexander renamed the variables but forgot to change sk_tx_queue_set()
2nd parameter.
if (queue_index != new_index)
sk_tx_queue_set(sk, queue_index);
This means we store -1 over and over in sk->sk_tx_queue_mapping
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
---
net/core/flow_dissector.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 0ff42f0..1929af8 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -352,7 +352,7 @@ u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
if (queue_index != new_index && sk &&
rcu_access_pointer(sk->sk_dst_cache))
- sk_tx_queue_set(sk, queue_index);
+ sk_tx_queue_set(sk, new_index);
queue_index = new_index;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] net: fix multiqueue selection
2013-09-07 19:02 [PATCH] net: fix multiqueue selection Eric Dumazet
@ 2013-09-08 4:08 ` Alexander Duyck
2013-09-11 20:13 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Alexander Duyck @ 2013-09-08 4:08 UTC (permalink / raw)
To: Eric Dumazet; +Cc: David Miller, netdev, Alexander Duyck
On 09/07/2013 12:02 PM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> commit 416186fbf8c5b4e4465 ("net: Split core bits of netdev_pick_tx
> into __netdev_pick_tx") added a bug that disables caching of queue
> index in the socket.
>
> This is the source of packet reorders for TCP flows, and
> again this is happening more often when using FQ pacing.
>
> Old code was doing
>
> if (queue_index != old_index)
> sk_tx_queue_set(sk, queue_index);
>
> Alexander renamed the variables but forgot to change sk_tx_queue_set()
> 2nd parameter.
>
> if (queue_index != new_index)
> sk_tx_queue_set(sk, queue_index);
>
> This means we store -1 over and over in sk->sk_tx_queue_mapping
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
> net/core/flow_dissector.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
> index 0ff42f0..1929af8 100644
> --- a/net/core/flow_dissector.c
> +++ b/net/core/flow_dissector.c
> @@ -352,7 +352,7 @@ u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
>
> if (queue_index != new_index && sk &&
> rcu_access_pointer(sk->sk_dst_cache))
> - sk_tx_queue_set(sk, queue_index);
> + sk_tx_queue_set(sk, new_index);
>
> queue_index = new_index;
> }
>
>
> --
Ugh, my bad. This is a nasty one too since the behaviour appeared to be
correct for most cases.
It looks like this needs to go into stable for 3.9 - 3.11.
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net: fix multiqueue selection
2013-09-08 4:08 ` Alexander Duyck
@ 2013-09-11 20:13 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2013-09-11 20:13 UTC (permalink / raw)
To: alexander.duyck; +Cc: eric.dumazet, netdev, alexander.h.duyck
From: Alexander Duyck <alexander.duyck@gmail.com>
Date: Sat, 07 Sep 2013 21:08:59 -0700
> On 09/07/2013 12:02 PM, Eric Dumazet wrote:
>> From: Eric Dumazet <edumazet@google.com>
>>
>> commit 416186fbf8c5b4e4465 ("net: Split core bits of netdev_pick_tx
>> into __netdev_pick_tx") added a bug that disables caching of queue
>> index in the socket.
>>
>> This is the source of packet reorders for TCP flows, and
>> again this is happening more often when using FQ pacing.
>>
>> Old code was doing
>>
>> if (queue_index != old_index)
>> sk_tx_queue_set(sk, queue_index);
>>
>> Alexander renamed the variables but forgot to change sk_tx_queue_set()
>> 2nd parameter.
>>
>> if (queue_index != new_index)
>> sk_tx_queue_set(sk, queue_index);
>>
>> This means we store -1 over and over in sk->sk_tx_queue_mapping
>>
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
...
> Ugh, my bad. This is a nasty one too since the behaviour appeared to be
> correct for most cases.
>
> It looks like this needs to go into stable for 3.9 - 3.11.
>
> Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-09-07 19:02 [PATCH] net: fix multiqueue selection Eric Dumazet
2013-09-08 4:08 ` Alexander Duyck
2013-09-11 20:13 ` David Miller
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