From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC PATCH 00/17] virtual-bus Date: Fri, 03 Apr 2009 14:54:02 +0300 Message-ID: <49D5F8DA.20400@redhat.com> References: <20090402085253.GA29932@gondor.apana.org.au> <49D47F11.6070400@redhat.com> <49D5EBE1.8030200@redhat.com> <49D5ED11.2000800@redhat.com> <20090403111242.GA10200@gondor.apana.org.au> <49D5F6FC.5090401@redhat.com> <20090403114828.GA10465@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Gerd Hoffmann , ghaskins@novell.com, anthony@codemonkey.ws, andi@firstfloor.org, linux-kernel@vger.kernel.org, agraf@suse.de, pmullaney@novell.com, pmorreale@novell.com, rusty@rustcorp.com.au, netdev@vger.kernel.org, kvm@vger.kernel.org To: Herbert Xu Return-path: Received: from mx2.redhat.com ([66.187.237.31]:45523 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754165AbZDCLxl (ORCPT ); Fri, 3 Apr 2009 07:53:41 -0400 In-Reply-To: <20090403114828.GA10465@gondor.apana.org.au> Sender: kvm-owner@vger.kernel.org List-ID: Herbert Xu wrote: > On Fri, Apr 03, 2009 at 02:46:04PM +0300, Avi Kivity wrote: > >> The host writes the packet to tap, at which point it is consumed from >> its point of view. The host would like to mention that if there was an >> API to notify it when the packet was actually consumed, then it would >> gladly use it. Bonus points if this involves not copying the packet. >> > > We're using write(2) for this, no? Yes. > That should invoke netif_rx_ni > which blocks until the packet is "processed", which usually means > that it's placed on the NIC's hardware queue. > It doesn't copy and queue the packet? We use O_NONBLOCK and poll() so we can tell when we can queue without blocking. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.