Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932572Ab1EQW6W (ORCPT ); Tue, 17 May 2011 18:58:22 -0400 Received: from mail-qw0-f46.google.com ([209.85.216.46]:50371 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932485Ab1EQW6V convert rfc822-to-8bit (ORCPT ); Tue, 17 May 2011 18:58:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=QtHW4sXgj6cDWMcawkzBxA0EUHUkaiJJOExJVPMJeYMOZdVidAGQajmWAiBNlvtdd7 WNGkkl+1gEAez+OeFOkSGieGgGR2b5SgzQavIy/4FXHQmzs+ddI6CzGm0vhY7E92b2D5 UftXCX7pvLfLLetRoMpUewsy8EBQPvgDvrOXU= MIME-Version: 1.0 In-Reply-To: <1305671318.10756.49.camel@localhost.localdomain> References: <1305574128.3456.23.camel@localhost.localdomain> <1305574518.2885.25.camel@bwh-desktop> <1305574680.3456.33.camel@localhost.localdomain> <1305575253.2885.28.camel@bwh-desktop> <20110516211459.GE18148@redhat.com> <1305588738.3456.65.camel@localhost.localdomain> <1305671318.10756.49.camel@localhost.localdomain> From: =?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= Date: Wed, 18 May 2011 00:58:00 +0200 Message-ID: Subject: Re: [PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice To: Shirley Ma Cc: "Michael S. Tsirkin" , Ben Hutchings , David Miller , Eric Dumazet , Avi Kivity , Arnd Bergmann , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1140 Lines: 28 W dniu 18 maja 2011 00:28 u?ytkownik Shirley Ma napisa?: > On Tue, 2011-05-17 at 23:48 +0200, Micha? Miros?aw wrote: >> 2011/5/17 Shirley Ma : >> > Looks like to use a new flag requires more time/work. I am thinking >> > whether we can just use HIGHDMA flag to enable zero-copy in macvtap >> to >> > avoid the new flag for now since mavctap uses real NICs as lower >> device? >> >> Is there any other restriction besides requiring driver to not recycle >> the skb? Are there any drivers that recycle TX skbs? > Not more other restrictions, skb clone is OK. pskb_expand_head() looks > OK to me from code review. > Currently there is no drivers recycle TX skbs. So why do you require the target device to have some flags at all? Do I understand correctly, that this zero-copy feature is about packets received from VMs? Best Regards, Micha? Miros?aw -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/