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From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next-2.6] net_sched: TCQ_F_CAN_BYPASS generalization
Date: Fri, 21 Jan 2011 16:27:33 -0800 (PST)
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 21 Jan 2011 12:04:41 +0100

> Now qdisc stab is handled before TCQ_F_CAN_BYPASS test in
> __dev_xmit_skb(), we can generalize TCQ_F_CAN_BYPASS to other qdiscs
> than pfifo_fast : pfifo, bfifo, pfifo_head_drop and sfq
> 
> SFQ is special because it can have external classifiers, and in these
> cases, we cannot bypass queue discipline (packet could be dropped by
> classifier) without admin asking it, or further changes.
> 
> Its worth doing this, especially for SFQ, avoiding dirtying memory in
> case no packets are already waiting in queue.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, thanks.

> I am not sure RED can use bypass too, feel free to comment on this ;)

The only thing that RED would seem to care about would be the
queue size average calculation.