From: Alex Tomas Subject: Re: [RFC] delayed allocation for ext4 Date: Sat, 23 Dec 2006 22:09:57 +0300 Message-ID: References: <20061223033123.GL44411608@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alex Tomas , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from ppp85-141-207-24.pppoe.mtu-net.ru ([85.141.207.24]:60414 "EHLO gw.home.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753677AbWLWTKJ (ORCPT ); Sat, 23 Dec 2006 14:10:09 -0500 To: David Chinner In-Reply-To: <20061223033123.GL44411608@melbourne.sgi.com> (David Chinner's message of "Sat\, 23 Dec 2006 14\:31\:23 +1100") Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Good day, >>>>> David Chinner (DC) writes: DC> So that mean's we'll have 2 separate mechanisms for marking DC> pages as delalloc. XFS uses the BH_delay flag to indicate DC> that a buffer (block) attached to the page is using delalloc. well, for blocksize=pagesize we can save 56 bytes on every page. DC> FWIW, how does this mechanism deal with block size < page size? DC> Don't you have to track delalloc on a block basis rather than DC> a page basis? I'm still thinking how better to deal with that w/o much code duplication. DC> Ah, that's why you can get away with a page flag - you've ignored DC> the partial page delay state problem. Any plans to use the DC> existing method in the future so we will be able to use ext4 delalloc DC> on machines with a page size larger than 4k? what do you mean by "exsiting"? BH_delay? thanks, Alex