From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 25 Apr 2007 12:17:15 -0700 (PDT) From: Christoph Lameter Subject: Re: [RFC][PATCH] syctl for selecting global zonelist[] order In-Reply-To: <20070425121946.9eb27a79.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20070425121946.9eb27a79.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: LKML , Linux-MM , GOTO List-ID: On Wed, 25 Apr 2007, KAMEZAWA Hiroyuki wrote: > Make zonelist policy selectable from sysctl. > > Assume 2 node NUMA, only node(0) has ZONE_DMA (ZONE_DMA32). > > In this case, default (node0's) zonelist order is > > Node(0)'s NORMAL -> Node(0)'s DMA -> Node(1)"s NORMAL. > > This means Node(0)'s DMA is used before Node(1)'s NORMAL. So a IA64 platform with i386 sicknesses? And pretty bad case of it since I assume that the memory sizes per node are equal. Your solution of taking 4G off node 0 and then going to node 1 first must hurt some processes running on node 0. But there is no easy solution since the hardware is badly screwed up with 32 bit I/O. Whatever you do the memory balance between the two nodes is making the system behave in an unsymmetric way. > In some server, some application uses large memory allcation. > This exhaust memory in the above order. Could we add a boot time option instead that changes the zonelist build behavior? Maybe an arch hook that can deal with it? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org