Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754416Ab0FYCIo (ORCPT ); Thu, 24 Jun 2010 22:08:44 -0400 Received: from mga11.intel.com ([192.55.52.93]:15973 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753156Ab0FYCIm convert rfc822-to-8bit (ORCPT ); Thu, 24 Jun 2010 22:08:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,478,1272870000"; d="scan'208";a="579709947" From: "Xin, Xiaohui" To: Herbert Xu , "Dong, Eddie" CC: Stephen Hemminger , "netdev@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mst@redhat.com" , "mingo@elte.hu" , "davem@davemloft.net" , "jdike@linux.intel.com" Date: Fri, 25 Jun 2010 10:07:34 +0800 Subject: RE: [RFC PATCH v7 01/19] Add a new structure for skb buffer from external. Thread-Topic: [RFC PATCH v7 01/19] Add a new structure for skb buffer from external. Thread-Index: AcsThT/Rm7uoRx/+TDOLr+CCct8P8gAhaLEg Message-ID: References: <20100608052744.GA21547@gondor.apana.org.au> <20100611052112.GA25649@gondor.apana.org.au> <20100617112119.GB1515@gondor.apana.org.au> <1A42CE6F5F474C41B63392A5F80372B21F58CD9A@shsmsx501.ccr.corp.intel.com> <20100623095254.GA32491@gondor.apana.org.au> <1A42CE6F5F474C41B63392A5F80372B21F58CE7F@shsmsx501.ccr.corp.intel.com> <20100624100836.GA16220@gondor.apana.org.au> In-Reply-To: <20100624100836.GA16220@gondor.apana.org.au> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1830 Lines: 38 Herbert, That's why I have sent you the patch for guest virtio-net driver. I reserved 512 bytes in each page, then I can always have the space to copy and avoid the backend memory used up issue. Thanks Xiaohui >-----Original Message----- >From: Herbert Xu [mailto:herbert@gondor.apana.org.au] >Sent: Thursday, June 24, 2010 6:09 PM >To: Dong, Eddie >Cc: Xin, Xiaohui; Stephen Hemminger; netdev@vger.kernel.org; kvm@vger.kernel.org; >linux-kernel@vger.kernel.org; mst@redhat.com; mingo@elte.hu; davem@davemloft.net; >jdike@linux.intel.com >Subject: Re: [RFC PATCH v7 01/19] Add a new structure for skb buffer from external. > >On Wed, Jun 23, 2010 at 06:05:41PM +0800, Dong, Eddie wrote: >> >> I mean once the frontend side driver post the buffers to the backend driver, the backend >driver will "immediately" use that buffers to compose skb or gro_frags and post them to the >assigned host NIC driver as receive buffers. In that case, if the backend driver recieves a >packet from the NIC that requires to do copy, it may be unable to find additional free guest >buffer because all of them are already used by the NIC driver. We have to reserve some guest >buffers for the possible copy even if the buffer address is not identified by original skb :( > >OK I see what you mean. Can you tell me how does Xiaohui's >previous patch-set deal with this problem? > >Thanks, >-- >Visit Openswan at http://www.openswan.org/ >Email: Herbert Xu ~{PmV>HI~} >Home Page: http://gondor.apana.org.au/~herbert/ >PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- 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/