From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH] xen-netfront: pull on receive skb may need to happen earlier Date: Mon, 08 Jul 2013 13:41:44 +0100 Message-ID: <51DACFA802000078000E343D@nat28.tlf.novell.com> References: <8511913.uMAmUdIO30@eistomin.edss.local> <20130517085923.GC14401@zion.uk.xensource.com> <51D57C1F.8070909@hunenet.nl> <20130704150137.GW7483@zion.uk.xensource.com> <51D6AED902000078000E2EA9@nat28.tlf.novell.com> <20130705145319.GB9050@zion.uk.xensource.com> <51DAA9B202000078000E3357@nat28.tlf.novell.com> <51DAAD92.4010708@hunenet.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Cc: "Ian Campbell" , "Wei Liu" , , , , To: "Dion Kant" Return-path: Received: from nat28.tlf.novell.com ([130.57.49.28]:48193 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751379Ab3GHMlv convert rfc822-to-8bit (ORCPT ); Mon, 8 Jul 2013 08:41:51 -0400 In-Reply-To: <51DAAD92.4010708@hunenet.nl> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: >>> On 08.07.13 at 14:16, Dion Kant wrote: > I was wondering about the following. > > In netif_poll(struct napi_struct *napi, int budget) the skb->cb is assigend, > but it may be clipped to RX_COPY_THRESHOLD > > NETFRONT_SKB_CB(skb)->pull_to = rx->status; > if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD) > NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD; > > How does this modification of NETFRONT_SKB_CB(skb)->pull_to propagates > or is this irrelevant? I'm not sure I understand what you're asking. pull_to is a private (to netfront) field used to communicate how much of the skb needs to be pulled. I don't see how the word "propagate" makes any sense here, but as said I may simply not be getting what you're asking about. Jan