Subject: Re: [net] net: sched: shrink struct qdisc_skb_cb to 28 bytes

From: Doug Ledford <[email-masked]>
Date: Thu, 18 Sep 2014 18:29:31 -0400

On 09/18/2014 11:02 AM, Eric Dumazet wrote:
> From: Eric Dumazet <[email-masked]>
>
> We cannot make struct qdisc_skb_cb bigger without impacting IPoIB,
> or increasing skb->cb[] size.
>
> Commit e0f31d849867 ("flow_keys: Record IP layer protocol in
> skb_flow_dissect()") broke IPoIB.
>
> Only current offender is sch_choke, and this one do not need an
> absolutely precise flow key.
>
> If we store 17 bytes of flow key, its more than enough. (Its the actual
> size of flow_keys if it was a packed structure, but we might add new
> fields at the end of it later)
>
> Signed-off-by: Eric Dumazet <[email-masked]>
> Fixes: e0f31d849867 ("flow_keys: Record IP layer protocol in skb_flow_dissect()")

I've installed this patch on my cluster and it resolves the problem.

Tested-by/Acked-by: Doug Ledford <[email-masked]>