From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43E04567.5070603@jp.fujitsu.com> Date: Wed, 01 Feb 2006 14:21:43 +0900 From: KAMEZAWA Hiroyuki MIME-Version: 1.0 Subject: Re: [RFC][PATCH] remove zone_mem_map [3/4] pfn_to_page() References: <43E02AAC.7050104@jp.fujitsu.com> <43E04206.8030104@mbligh.org> In-Reply-To: <43E04206.8030104@mbligh.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: linux-mm , Andy Whitcroft List-ID: Martin J. Bligh wrote: > KAMEZAWA Hiroyuki wrote: >> Replace page_to_pfn() functions which uses zone->zone_mem_map. >> >> Although pfn_to_page() uses node->node_mem_map, page_to_pfn() uses >> zone->zone_mem_map. I don't know why. This patch make page_to_pfn >> use node->node_mem_map > > I think that might have been because it's a faster op, at least on > some architectures, under sparsemem. Andy, can you confirm / deny? > Some part of the mapping was embedded in the page flags. > Under sparsemem, zone->zone_mem_map is meaningless. The mem_map is not contiguous. If NODE_DATA(nid) is slower than page_zone() , this change will be problem. While page_zone() accesses global zone_table[], NODE_DATA(nid) depends on each arch. Some archs has local NODE_DATA table. > If Andy can't recall, I'll look again on Thursday when I'm back ... > > M. > Thank you!. -Kame -- 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