From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756075AbXD0Qpp (ORCPT ); Fri, 27 Apr 2007 12:45:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756077AbXD0Qpp (ORCPT ); Fri, 27 Apr 2007 12:45:45 -0400 Received: from thunk.org ([69.25.196.29]:39759 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756075AbXD0Qpo (ORCPT ); Fri, 27 Apr 2007 12:45:44 -0400 Date: Fri, 27 Apr 2007 12:45:35 -0400 From: Theodore Tso To: Andrew Morton Cc: David Chinner , clameter@sgi.com, linux-kernel@vger.kernel.org, Mel Gorman , William Lee Irwin III , Jens Axboe , Badari Pulavarty , Maxim Levitsky Subject: Re: [00/17] Large Blocksize Support V3 Message-ID: <20070427164535.GH24852@thunk.org> Mail-Followup-To: Theodore Tso , Andrew Morton , David Chinner , clameter@sgi.com, linux-kernel@vger.kernel.org, Mel Gorman , William Lee Irwin III , Jens Axboe , Badari Pulavarty , Maxim Levitsky References: <20070424222105.883597089@sgi.com> <20070426190438.3a856220.akpm@linux-foundation.org> <20070427022731.GF65285596@melbourne.sgi.com> <20070426195357.597ffd7e.akpm@linux-foundation.org> <20070427042046.GI65285596@melbourne.sgi.com> <20070426221528.655d79cb.akpm@linux-foundation.org> <20070427060921.GA77450368@melbourne.sgi.com> <20070427000403.6013d1fa.akpm@linux-foundation.org> <20070427080321.GG32602149@melbourne.sgi.com> <20070427014849.41f383f7.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070427014849.41f383f7.akpm@linux-foundation.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 27, 2007 at 01:48:49AM -0700, Andrew Morton wrote: > And other filesystems (ie: ext4) _might_ use it. But ext4 is extent-based, > so perhaps it's not work churning the on-disk format to get a bit of a > boost in the block allocator. Well, ext3 could definitely use it; there are people using 8k and 16k blocksizes on ia64 systems today. Those filesystems can't be mounted on x86 or x86_64 systems because our pagesize is 4k, though. And I imagine that ext4 might want to use a large blocksize too --- after all, XFS is extent based as well, and not _all_ of the advantages of using a larger blocksize are related to brain-damaged storage subsystems with short SG list support. Whether the advantages offset the internal fragmentation overhead or the complexity of adding fragments support is a different question, of course. So while the jury is out about how many other filesystems might use it, I suspect it's more than you might think. At the very least, there may be some IA64 users who might be trying to transition their way to x86_64, and have existing filesystems using a 8k or 16k block filesystems. :-) - Ted