From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754168AbXD0KQH (ORCPT ); Fri, 27 Apr 2007 06:16:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755560AbXD0KQG (ORCPT ); Fri, 27 Apr 2007 06:16:06 -0400 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:29321 "HELO smtp107.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754168AbXD0KQE (ORCPT ); Fri, 27 Apr 2007 06:16:04 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=UETUHnUd963+V+XVNqoSuw0Ek7o54/FoxEHZbv8pp1JjqHEEKfgQTyD9oQPYSx16f6HPNpzrYiJIlrUYlAvdwV2Lzy/MsbcrvsmHlujmwm2g19QuEkTldMnIVv4+s+6426k8keiTuyB40Iza4VUGgR6f4zn28b20kDaZnp+/9Eo= ; X-YMail-OSG: cr0rhKQVM1lBDDr1X2ikfuX3OyJPejg6hGuRJrHe9Qme231B1u8P2V6zKvUwxcS8dr7efOrS5g-- Message-ID: <4631CD58.8010103@yahoo.com.au> Date: Fri, 27 Apr 2007 20:15:52 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Christoph Lameter CC: "Eric W. Biederman" , linux-kernel@vger.kernel.org, Mel Gorman , William Lee Irwin III , David Chinner , Jens Axboe , Badari Pulavarty , Maxim Levitsky Subject: Re: [00/17] Large Blocksize Support V3 References: <20070424222105.883597089@sgi.com> <46303A98.9000605@yahoo.com.au> <46304C74.9040304@yahoo.com.au> <46305177.7060102@yahoo.com.au> <463057D9.9030804@yahoo.com.au> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Christoph Lameter wrote: > On Thu, 26 Apr 2007, Nick Piggin wrote: > > >>>But what do you mean with it? A block is no longer a contiguous section of >>>memory. So you have redefined the term. >> >>I don't understand what you mean at all. A block has always been a >>contiguous area of disk. > > > You want to change the block layer to support larger blocksize than > PAGE_SIZE right? So you need to segment that larger block into pieces. The block is the disk block, which does not get segmented. What you have is a small layer that tells you which block a pagecache page points to, and which pagecache page refers to a given block. Just like we have now only slightly extended. >>>And you dont care about Mel's work on that level? >> >>I actually don't like it too much because it can't provide a robust >>solution. What do you do on systems with small memories, or those that >>eventually do get fragmented? > > > You could f.e. switch off defragmentation and the large block support? Ahh, then you reboot your machine to access your other filesystems? >>Actually, I don't know why people are so excited about being able to >>use higher order allocations (I would rather be more excited about >>never having to use them). But for those few places that really need >>it, I'd rather see them use a virtually mapped kernel with proper >>defragmentation rather than putting hacks all through the core code. > > > Ahh. I knew we were going this way.... Now we have virtual contiguous vs. > physical discontiguous.... Yuck hackidihack. That gives you have the proper infrastructure that is needed to actually support higher order _physical_ allocations _properly_. -- SUSE Labs, Novell Inc.