From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from proxy.6wind.com (host.76.145.23.62.rev.coltfrance.com [62.23.145.76]) by dpdk.org (Postfix) with ESMTP id 570D2C462 for ; Wed, 15 Jun 2016 14:03:14 +0200 (CEST) Received: from [10.16.0.195] (unknown [10.16.0.195]) by proxy.6wind.com (Postfix) with ESMTP id 18CB527FB3; Wed, 15 Jun 2016 14:03:14 +0200 (CEST) To: "Hunt, David" , Jan Viktorin References: <1465919341-3209-1-git-send-email-david.hunt@intel.com> <1465976824-83823-1-git-send-email-david.hunt@intel.com> <20160615121358.5ef9f142@pcviktorin.fit.vutbr.cz> <57614043.9090603@intel.com> Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, shreyansh.jain@nxp.com From: Olivier MATZ Message-ID: <57614402.6020708@6wind.com> Date: Wed, 15 Jun 2016 14:03:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.6.0 MIME-Version: 1.0 In-Reply-To: <57614043.9090603@intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v12 0/3] mempool: add external mempool manager 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, 15 Jun 2016 12:03:14 -0000 Hi, On 06/15/2016 01:47 PM, Hunt, David wrote: > > > On 15/6/2016 11:13 AM, Jan Viktorin wrote: >> Hi, >> >> I've got one last question. Initially, I was interested in creating >> my own external memory provider based on a Linux Kernel driver. >> So, I've got an opened file descriptor that points to a device which >> can mmap a memory regions for me. >> >> ... >> int fd = open("/dev/uio0" ...); >> ... >> rte_mempool *pool = rte_mempool_create_empty(...); >> rte_mempool_set_ops_byname(pool, "uio_allocator_ops"); >> >> I am not sure how to pass the file descriptor pointer. I thought it would >> be possible by the rte_mempool_alloc but it's not... Is it possible >> to solve this case? >> >> The allocator is device-specific. >> >> Regards >> Jan > > This particular use case is not covered. > > We did discuss this before, and an opaque pointer was proposed, but did > not make it in. > http://article.gmane.org/gmane.comp.networking.dpdk.devel/39821 > (and following emails in that thread) > > So, the options for this use case are as follows: > 1. Use the pool_data to pass data in to the alloc, then set the > pool_data pointer before coming back from alloc. (It's a bit of a hack, > but means no code change). > 2. Add an extra parameter to the alloc function. The simplest way I can > think of doing this is to > take the *opaque passed into rte_mempool_populate_phys, and pass it on > into the alloc function. > This will have minimal impact on the public API,s as there is already an > opaque there in the _populate_ funcs, we're just > reusing it for the alloc. > > Do others think option 2 is OK to add this at this late stage? Even if > the patch set has already been ACK'd? Jan's use-case looks to be relevant. What about changing: rte_mempool_set_ops_byname(struct rte_mempool *mp, const char *name) into: rte_mempool_set_ops(struct rte_mempool *mp, const char *name, void *opaque) ? The opaque pointer would be saved in mempool structure, and used when the mempool is populated (calling mempool_ops_alloc). The type of the structure pointed by the opaque has to be defined (and documented) into each mempool_ops manager. Olivier