Re: [PATCH net] net: sched: shrink struct qdisc_skb_cb to 28 bytes
From: Stephen Hemminger <stephen@networkplumber.org>
Date: 2014-09-18 16:26:39
On Thu, 18 Sep 2014 08:02:05 -0700 Eric Dumazet [off-list ref] wrote:
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>Can we add BUILD_BUG to stop next time something smacks this.