From: Eric Dumazet <redacted>
Date: Wed, 27 Aug 2014 06:23:58 -0700

On Wed, 2014-08-27 at 14:31 +0200, Hannes Frederic Sowa wrote:

quoted

One thing one should keep in mind is, that there must be a skb available
to trigger the flush, maybe this will hurt us one day.

Thinking more about it should we go with a coccinelle script and
replace/extend ndo_start_xmit with an additional argument?

This will be a pain for backports and things like that.

Agreed.

skb->xmit_more is a bit annoying, because it consumes one bit in all
skbs, while it could be one byte per cpu as ndo_start_xmit() is called
while BH are disabled.

It also forces a cache line dirtying, that will hurt qdisc like HTB
where skbs can be cooked/enqueued by remote cpus.

The xmit_more value sits in the same cache line as the queue number,
which also gets dirtied in the TX fast path.