Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757523Ab0HDRJP (ORCPT ); Wed, 4 Aug 2010 13:09:15 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:45788 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751815Ab0HDRJN (ORCPT ); Wed, 4 Aug 2010 13:09:13 -0400 Subject: RE: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net. From: Shirley Ma To: "Dong, Eddie" Cc: Arnd Bergmann , "Xin, Xiaohui" , "netdev@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mst@redhat.com" , "mingo@elte.hu" , "davem@davemloft.net" , "herbert@gondor.apana.org.au" , "jdike@linux.intel.com" In-Reply-To: <1A42CE6F5F474C41B63392A5F80372B228FCE7B1@shsmsx501.ccr.corp.intel.com> References: <1280402088-5849-1-git-send-email-xiaohui.xin@intel.com> <1280505112.9058.31.camel@localhost.localdomain> <201007311130.17000.arnd@arndb.de> <1A42CE6F5F474C41B63392A5F80372B228FCE7B1@shsmsx501.ccr.corp.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 04 Aug 2010 10:09:05 -0700 Message-ID: <1280941745.3391.15.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 (2.28.3-1.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 32 Hello Eddie, On Wed, 2010-08-04 at 10:06 +0800, Dong, Eddie wrote: > But zero-copy is a Linux generic feature that can be used by other > VMMs as well if the BE service drivers want to incorporate. If we can > make mp device VMM-agnostic (it may be not yet in current patch), that > will help Linux more. First other VMMs support tun/tap which provides most funcs but not zero copy. Second mp patch only supports zero copy for vhost now, macvtap zero copy will not be used by vhost only. Third, the current mp device doesn't fallback to copy when failure. So you can extend mp device to support all funcs, but the usage/funcs will be similar with macvtap, then either mp device will replace macvtap in the future with similar funcs or we can use enhance macvtap to support zero copy. It is not necessary to have both in Linux. I think it's better to implement zero copy in macvtap, tun/tap instead of creating a new mp device. Thanks Shirley -- 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/