From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: [RFC] ext4: block reservation allocation Date: Thu, 08 Mar 2012 11:39:11 -0500 Message-ID: <4F58E0AF.3010207@ubuntu.com> References: <20120227090901.GA13953@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org Return-path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120]:9309 "EHLO cdptpa-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757269Ab2CHQjN (ORCPT ); Thu, 8 Mar 2012 11:39:13 -0500 In-Reply-To: <20120227090901.GA13953@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2/27/2012 4:09 AM, Zheng Liu wrote: > Hi list, > > Now, in ext4, we have multi-block allocation and delay allocation. They work > well for most scenarios. However, in some specific scenarios, they cannot help > us to optimize block allocation. For example, the user may want to indicate some > file set to be allocated at the beginning of the disk because its speed in this > position is faster than its speed at the end of disk. I thought this could be done with the new defrag api. I thought it had a way to allocate a new donor file in a specific location so you could then migrate the target file to those specific donor blocks.