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 490CE1B185 for ; Tue, 25 Sep 2018 15:51:51 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Sep 2018 06:51:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,302,1534834800"; d="scan'208";a="265565444" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.55]) ([10.237.220.55]) by fmsmga005.fm.intel.com with ESMTP; 25 Sep 2018 06:51:32 -0700 To: Shreyansh Jain Cc: ferruh.yigit@intel.com, dev@dpdk.org References: <20180925125423.7505-1-shreyansh.jain@nxp.com> <20180925125423.7505-4-shreyansh.jain@nxp.com> <894130a9-017c-348d-31f8-c4c23f517f25@nxp.com> From: "Burakov, Anatoly" Message-ID: <67e25f1a-110c-db32-5f3b-a065e77fecc6@intel.com> Date: Tue, 25 Sep 2018 14:51:31 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <894130a9-017c-348d-31f8-c4c23f517f25@nxp.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH 3/5] common/dpaax: add library for PA VA translation table X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Sep 2018 13:51:51 -0000 On 25-Sep-18 2:39 PM, Shreyansh Jain wrote: > Hello Anatoly, > > On Tuesday 25 September 2018 06:58 PM, Burakov, Anatoly wrote: >> On 25-Sep-18 1:54 PM, Shreyansh Jain wrote: >>> A common library, valid for dpaaX drivers, which is used to maintain >>> a local copy of PA->VA translations. >>> >>> In case of physical addressing mode (one of the option for FSLMC, and >>> only option for DPAA bus), the addresses of descriptors Rx'd are >>> physical. These need to be converted into equivalent VA for rte_mbuf >>> and other similar calls. >>> >>> Using the rte_mem_virt2iova or rte_mem_virt2phy is expensive. This >>> library is an attempt to reduce the overall cost associated with >>> this translation. >>> >>> A small table is maintained, containing continuous entries >>> representing a continguous physical range. Each of these entries >>> stores the equivalent VA, which is fed during mempool creation, or >>> memory allocation/deallocation callbacks. >>> >>> Signed-off-by: Shreyansh Jain >>> --- >> >> Hi Shreyansh, >> >> So, basically, you're reimplementing old DPDK's memory view (storing >> VA's in a PA-centric way). Makes sense :) > > Yes, and frankly, I couldn't come up with any other way. > >> >> I should caution you that right now, external memory allocator >> implementation does *not* trigger any callbacks for newly added >> memory. So, anything coming from external memory will not be reflected >> in your table, unless it happens to be already there before >> dpaax_iova_table_populate() gets called. This patchset makes a good >> argument for why perhaps it should trigger callbacks. Thoughts? > > Oh. Then I must be finishing reading through your patches for external > memory sooner. I didn't realize this. To be clear, the current implementation of external memory allocators is not necessarily final - it's not too late to add callbacks to enable your use case better, if that's required (and it should be pretty easy to implement as well). -- Thanks, Anatoly