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

On Fri, Sep 19, 2014 at 1:29 AM, Doug Ledford [off-list ref] wrote:

On 09/18/2014 11:02 AM, Eric Dumazet wrote:

quoted

From: Eric Dumazet <edumazet@google.com>
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 <edumazet@google.com>
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 [off-list ref]

Thanks Eric/Doug!

Dave - just to make sure, this is for net, as the regression was
introduced in 3.17-rc1.

Or.