Subject: Re: [PATCH RFC 0/2] xfrm: Remove ancient sleeping code

From: Steffen Klassert <[email-masked]>
Date: Fri, 11 Oct 2013 11:21:45 +0200

On Fri, Oct 11, 2013 at 03:18:40PM +0800, Fan Du wrote:
> >>In xfrm policy queue, XFRM_MAX_QUEUE_LEN is 100, which means 101th skb
> >>will be dropped, how about make it configurable?
> >
> >IMO we would have yet another useless knob then. Currently we send all
> >packets by default to a blackhole as long as the state is not resolved
> >and most people are fine with it. The queueing is mostly to speed up
> >tcp handshakes,
> 
> I cannot follow on this part. Would you please mind to explain how making a
> policy queue will speed up TCP handshakes than orignal CAN_SLEEP mechanism?
> 

I have not said that queueing is any faster than the sleeping mechanism.
But it is faster than the current default that simply sends the first
packets to a blackhole and can be used regardless if we can sleep.

All I wanted to say is that there are not many packets needed to establish
tcp connections, so I think a 100 packets queue is sufficient.