From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Burakov, Anatoly" Subject: Re: Memory allocation in dpdk at basic level Date: Tue, 23 Oct 2018 10:56:18 +0100 Message-ID: <20c86454-227e-1f1e-fd76-84597f6c9154@intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: Avinash Chaurasia , dev@dpdk.org Return-path: Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by dpdk.org (Postfix) with ESMTP id 051961B464 for ; Tue, 23 Oct 2018 11:56:20 +0200 (CEST) In-Reply-To: Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 22-Oct-18 10:08 PM, Avinash Chaurasia wrote: > Hello, > I am not sure whether this is right list for posting this problem. I am > trying to understand how dpdk allocate memory. I tried digging code to > understand memory allocation of DPDK. So far I understood that memory is > allocated from a heap that dpdk maintains. However, this heap must be > allocated at some place. I failed to traceback any function (called from > heap_alloc()) that calls mmap to allocate memory. Please let me know when > this heap is created, which function call does that. > Thanks > Avinash > Hi Avinash, Here's a very high level overview. At initialization, we mmap() anonymous memory regions (eal_memory.c contains the code - both for legacy and non-legacy mode). Then, we map actual pages into that space either at init (in legacy mode) or as needed (in non-legacy mode). In legacy mode, pages are mapped into anonymous memory straight away (see legacy init code in eal_memory.c). For non-legacy, page allocation happens in eal_memalloc.c on request from malloc (see malloc_heap.c). In both cases, newly allocated pages are added to DPDK heap, and from there they can be used by the rest of DPDK using rte_malloc or rte_memzone_reserve API's. -- Thanks, Anatoly