From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id 3956CADE8 for ; Wed, 18 Feb 2015 10:49:02 +0100 (CET) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 18 Feb 2015 01:49:00 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,600,1418112000"; d="scan'208";a="679649749" Received: from irsmsx104.ger.corp.intel.com ([163.33.3.159]) by fmsmga002.fm.intel.com with ESMTP; 18 Feb 2015 01:48:59 -0800 Received: from irsmsx155.ger.corp.intel.com (163.33.192.3) by IRSMSX104.ger.corp.intel.com (163.33.3.159) with Microsoft SMTP Server (TLS) id 14.3.195.1; Wed, 18 Feb 2015 09:48:58 +0000 Received: from irsmsx105.ger.corp.intel.com ([169.254.7.117]) by irsmsx155.ger.corp.intel.com ([169.254.14.159]) with mapi id 14.03.0195.001; Wed, 18 Feb 2015 09:48:58 +0000 From: "Ananyev, Konstantin" To: "Richardson, Bruce" , Olivier MATZ Thread-Topic: [dpdk-dev] [PATCH 2/2] Remove RTE_MBUF_REFCNT references Thread-Index: AQHQSgLlubcXB2CIb0Ksk8gcVlJrSpz2I0IAgAAFSACAAAIAoA== Date: Wed, 18 Feb 2015 09:48:58 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258213EF5E4@irsmsx105.ger.corp.intel.com> References: <1424102913-18944-1-git-send-email-sergio.gonzalez.monroy@intel.com> <1424102913-18944-3-git-send-email-sergio.gonzalez.monroy@intel.com> <54E45888.7070603@6wind.com> <20150218093548.GA14884@bricha3-MOBL3> In-Reply-To: <20150218093548.GA14884@bricha3-MOBL3> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH 2/2] Remove RTE_MBUF_REFCNT references X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Feb 2015 09:49:02 -0000 Hi lads, > -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson > Sent: Wednesday, February 18, 2015 9:36 AM > To: Olivier MATZ > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 2/2] Remove RTE_MBUF_REFCNT references >=20 > On Wed, Feb 18, 2015 at 10:16:56AM +0100, Olivier MATZ wrote: > > Hi Sergio, > > > > On 02/16/2015 05:08 PM, Sergio Gonzalez Monroy wrote: > > >This patch removes all references to RTE_MBUF_REFCNT, setting the refc= nt > > >field in the mbuf struct permanently. > > > > > >Signed-off-by: Sergio Gonzalez Monroy > > > > I think removing the refcount compile option goes in the right > > direction. However, activating the refcount will break the applications > > that reserve a private zone in mbufs. This is due to the macros > > RTE_MBUF_TO_BADDR() and RTE_MBUF_FROM_BADDR() that suppose that > > the beginning of the mbuf is 128 bytes (sizeof mbuf) before the > > data buffer. > > >=20 > While I understand how the macros make certain assumptions, how does acti= vating > the refcnt specifically lead to the problems you describe? Could you expl= ain > that part in a bit more detail? >=20 > Thanks, > /Bruce >=20 Olivier, I also don't understand your concern here. As I can see, that patch has nothing to do with RTE_MBUF_FROM_BADDR/ RTE_MB= UF_FROM_BADDR macros. They are still there, for example rte_pktmbuf_detach() still uses it to res= tore mbuf's buf_addr. The only principal change here, is that we don't rely more on RTE_MBUF_FRO= M_BADDR to determine, Is that indirect mbuf or not.=20 Instead we use a special falg for that purpose: -#define RTE_MBUF_INDIRECT(mb) (RTE_MBUF_FROM_BADDR((mb)->buf_addr) !=3D = (mb)) +#define RTE_MBUF_INDIRECT(mb) (mb->ol_flags & IND_ATTACHED_MBUF) =20 BTW, Sergio as I said before, I think it should be: #define RTE_MBUF_INDIRECT(mb) ((mb)->ol_flags & IND_ATTACHED_MBUF) Konstantin > > For RTE_MBUF_TO_BADDR(), it's relatively easy to replace it. The > > mbuf pool could store the size of the private size like it's done > > for mbp_priv->mbuf_data_room_size. Using rte_mempool_from_obj(m) > > or m->pool, we can retrieve the mbuf pool and this value, then > > compute the buffer address. > > > > For RTE_MBUF_FROM_BADDR(), it's more complex. We could ensure that > > a backpointer to the mbuf is always located before the data buffer, > > but it looks difficult to do. > > > > Another idea would be to add a field in indirect mbufs that stores > > the pointer to the "parent" mbuf. > > > > Regards, > > Olivier > >