Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751464AbWHRSUr (ORCPT ); Fri, 18 Aug 2006 14:20:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751466AbWHRSUr (ORCPT ); Fri, 18 Aug 2006 14:20:47 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:25296 "EHLO fgwmail6.fujitsu.co.jp") by vger.kernel.org with ESMTP id S1751464AbWHRSUq (ORCPT ); Fri, 18 Aug 2006 14:20:46 -0400 Date: Sat, 19 Aug 2006 03:19:16 +0900 From: KAMEZAWA Hiroyuki To: Christoph Lameter Cc: manfred@colorfullife.com, ak@muc.de, mpm@selenic.com, marcelo@kvack.org, linux-kernel@vger.kernel.org, nickpiggin@yahoo.com.au, ak@suse.de, dgc@sgi.com Subject: Re: [MODSLAB 3/7] A Kmalloc subsystem Message-Id: <20060819031916.85d5979e.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20060816022238.13379.24081.sendpatchset@schroedinger.engr.sgi.com> <20060816022253.13379.76984.sendpatchset@schroedinger.engr.sgi.com> <20060816094358.e7006276.ak@muc.de> <44E3FC4F.2090506@colorfullife.com> <20060818161739.f7581645.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed version 2.2.0 (GTK+ 2.6.10; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 47 On Fri, 18 Aug 2006 09:58:13 -0700 (PDT) Christoph Lameter wrote: > On Fri, 18 Aug 2006, KAMEZAWA Hiroyuki wrote: > > > Just a note: with SPARSEMEM, we need more calculation and access to > > mem_section[] table and page structs(mem_map). > > Uhh, a regression against DISCONTIG. Could you address that issue? > At first, ia64's DISCONTIG is special because of VIRTUAL_MEMMAP. and ia64's SPARSEMEM is special,too. it's SPARSEMEM_EXTREME. Considering generic arch, see include/asm-generic/memory_model.h, which doesn't use virtual mem_map. with FLATMEM, pfn_to_page() is pfn + mem_map. just an address calclation. with *usual* DISCONTIG -- pgdat = NODE_DATA(pfn_to_nid(pfn)); page = pgdat->node_mem_map + pfn - pgdat->node_start_pfn -- if accessing to pgdat is fast, cost will not be big problem. pfn_to_nid() is usually implemeted by calclation or table look up. and usual SPARSEMEM, (not EXTREME) -- page = mem_section[(pfn >> SECTION_SHIFT)].mem_map + pfn -- need one table look up. maybe not very big. with SPARSEMEM_EXTREME -- page = mem_section[(pfn >> SECTION_SHIFT)][(pfn & MASK)].mem_map + pfn -- need one (big)table look up. -Kame - 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/