Subject: Re: [PATCH 00/28] Swap over NFS -v16

From: Peter Zijlstra <[email-masked]>
Date: Fri, 07 Mar 2008 12:55:31 +0100

On Fri, 2008-03-07 at 12:17 +0100, Peter Zijlstra wrote:

> That would be so if the whole path from RX to socket demux would have
> hard-irqs disabled. However I didn't see that. Moreover I think the
> whole purpose of the NetPoll interface is to allow some RX queueing to
> cut down on softirq overhead.

s/NetPoll/NAPI/

More specifically look at net/core/dev.c:netif_rx()
It has a input queue per device.

> >   2/ If the host is routing network packets, then incoming packets
> >      might go on an outbound queue.  Is this space limited?  and
> >      included in the reserve?
> 
> Not sure, somewhere along the routing code I lost it again. Constructive
> input from someone versed in that part of the kernel would be most
> welcome.

To clarify, I think we just send it on as I saw no reason why that could
fail. However the more fancy stuff like engress or QoS might spoil the
party, that is where I lost track.