From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Memory allocation in NUMA system Date: Fri, 25 Jul 2008 07:53:33 +0100 Message-ID: References: <488949B3.7080205@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <488949B3.7080205@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Yang, Xiaowei" , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 25/7/08 04:34, "Yang, Xiaowei" wrote: > Let's say we have a 2-node system, with node0 and node1's memory range > being 0-0xc0000000 (<4G) and 0x100000000-0x1c0000000 (>4G) respectively. > In that case, node1's memory is always preferred for domain memory > allocation, no matter which node the created domain is pinned to. It > results in performance penalty. > > One possible fix is to specify all range for the domain memory > allocation, which means local memory is preferred. This change may be > restricted only to the domain pinned to one node for less impact. > > One side effect is that the DMA memory size may be smaller, which makes > device domain unhappy. This can be addressed by reserving node0 to be > used lastly. Doesn't your solution amount to what we already do, for the 2-node example? i.e., node0 would not be chosen until node1 is exhausted? -- Keir