Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261732AbUJ1PrC (ORCPT ); Thu, 28 Oct 2004 11:47:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261721AbUJ1Pod (ORCPT ); Thu, 28 Oct 2004 11:44:33 -0400 Received: from jade.aracnet.com ([216.99.193.136]:58784 "EHLO jade.spiritone.com") by vger.kernel.org with ESMTP id S261740AbUJ1PkS (ORCPT ); Thu, 28 Oct 2004 11:40:18 -0400 Date: Thu, 28 Oct 2004 08:40:04 -0700 From: "Martin J. Bligh" To: Christoph Lameter , akpm@osdl.org cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: NUMA node swapping V3 Message-ID: <1275120000.1098978003@[10.10.2.4]> In-Reply-To: References: X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1475 Lines: 34 > Changes from V2: better documentation, fix missing #ifdef > > In a NUMA systems single nodes may run out of memory. This may occur even > by only reading from files which will clutter node memory with cached > pages from the file. > > However, as long as the system as a whole does have enough memory > available, kswapd is not run at all. This means that a process allocating > memory and running on a node that has no memory left, will get memory > allocated from other nodes which is inefficient to handle. It would be > better if kswapd would throw out some pages (maybe some of the cached > pages from files that have only once been read) to reclaim memory in the > node. > > The following patch checks the memory usage after each allocation in a > zone. If the allocation in a zone falls below a certain minimum, kswapd is > started for that zone alone. > > The minimum may be controlled through /proc/sys/vm/node_swap which is set > to zero by default and thus is off. > > If it is set for example to 100 then kswapd will be run on > a zone/node if less than 10% of pages are available after an allocation. I thought even the SGI people were saying this wouldn't actually help you, due to some workload issues? M. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/