From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932333AbWFZL1D (ORCPT ); Mon, 26 Jun 2006 07:27:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932447AbWFZL1D (ORCPT ); Mon, 26 Jun 2006 07:27:03 -0400 Received: from ug-out-1314.google.com ([66.249.92.168]:30304 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S932333AbWFZL1C (ORCPT ); Mon, 26 Jun 2006 07:27:02 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:reply-to:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:from; b=mT/IOimmedjWEXdmF0YOuUSP2AkAYwsTa7ZNZ4RtJithesIiU5SbsPooU/o+oaD+2N+9TdltDfYJVCFd7B9phss+WUj/qkGV1Vng6p0nfFx+z/hFbxf7rWPB5qJVDQiHIHebTYJtqo0EZL9TqjymI6+VA0hYGks9NwIrcwrScRs= Message-ID: <449FC592.8050409@innova-card.com> Date: Mon, 26 Jun 2006 13:31:30 +0200 Reply-To: Franck User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: Mel Gorman CC: Franck , Andrew Morton , Linux Kernel Mailing List Subject: Re: 2.6.17-mm1 References: <20060621034857.35cfe36f.akpm@osdl.org> <449AB01A.5000608@innova-card.com> <449ABC3E.5070609@innova-card.com> <20060623102037.GA1973@skynet.ie> <449BDCF5.6040808@innova-card.com> <20060623134634.GA6071@skynet.ie> <449C036D.6060004@innova-card.com> <20060623151322.GA13130@skynet.ie> <449C0DF3.601@innova-card.com> <449F9B4C.6000404@innova-card.com> In-Reply-To: Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit From: Franck Bui-Huu Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mel Gorman wrote: > > Architectures will not always have a known fixed start of physical > memory. On IA64 at least, they initialise memory as if it starts at 0 > but on my one test machine, the beginning part is always a memory hole. in that case ARCH_PFN_OFFSET is 0 which is the old behaviour, nothing change... > I've seen nothing to indicate that this hole will be the same size on > all IA64 machines but I kinda doubt it. Also, arches that use > init_bootmem() do not necessary use free_area_init(). > but in that case do they use ARCH_PFN_OFFSET != 0 ? if so that would be very surprising. That would meand "I have a hole a the start of my mem, I don't know at compile time where it starts, but I state that my physical mem start at ARCH_PFN_OFFSET anyways" >> If we don't change init_bootmem() to use ARCH_PFN_OFFSET, then the >> kernel will initialise the start of memory to 0 which is boggus. >> IOW, >> we can't use this function without this change (except if your memory >> start at 0 of course). And I think that init_bootmem() has been >> implemented for systems which have only one node _whatever_ memory >> start value... >> > > While you may be right, it'll only fix the problem for arches with > ARCH_PFN_OFFSET and using init_bootmem (which is the case of MIPS I > guess). But arches using init_bootmem_node or not using free_area_init() > may still get kicked. > Again in these cases, I doubt that they will setup ARCH_PFN_OFFSET... Franck