Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754318Ab0H3BFl (ORCPT ); Sun, 29 Aug 2010 21:05:41 -0400 Received: from mga01.intel.com ([192.55.52.88]:1408 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753127Ab0H3BFj (ORCPT ); Sun, 29 Aug 2010 21:05:39 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.56,289,1280732400"; d="scan'208";a="833014553" Subject: Re: [RFC v2 PATCH 0/6] Btrfs: Add hot data relocation functionality From: Shaohua Li To: Hubert Kario Cc: "bchociej@gmail.com" , "chris.mason@oracle.com" , "linux-btrfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "cmm@us.ibm.com" , "bcchocie@us.ibm.com" , "mrlupfer@us.ibm.com" , "crscott@us.ibm.com" , "mlupfer@gmail.com" , "conscott@vt.edu" In-Reply-To: <201008300242.27331.hka@qbs.com.pl> References: <1281651726-23501-1-git-send-email-bchociej@gmail.com> <20100826021343.GA452@sli10-conroe.sh.intel.com> <201008300242.27331.hka@qbs.com.pl> Content-Type: text/plain; charset="UTF-8" Date: Mon, 30 Aug 2010 09:05:29 +0800 Message-ID: <1283130329.16633.2.camel@sli10-conroe.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 39 On Mon, 2010-08-30 at 08:42 +0800, Hubert Kario wrote: > On Thursday 26 of August 2010 04:13:43 Shaohua Li wrote: > > On Fri, Aug 13, 2010 at 06:22:00AM +0800, bchociej@gmail.com wrote: > > > - Hooks in existing Btrfs functions to track data access frequency > > > > > > (btrfs_direct_IO, btrfs_readpages, and extent_write_cache_pages) > > > > > > - New rbtrees for tracking access frequency of inodes and sub-file > > > > > > ranges (hotdata_map.c) > > > > > > - A hash list for indexing data by its temperature (hotdata_hash.c) > > > > > > - A debugfs interface for dumping data from the rbtrees (debugfs.c) > > > > > > - A background kthread for relocating data to faster media based on > > > > > > temperature > > > > Hi, > > I'm wondering if the temperature info can be exported to userspace, and > > let a daemon to do the relocation (by ioctl). A userspace daemon is more > > flexible. > > Flexibility of userspace daemon is one thing, the ability to let the admin > precisely control on which drive data is placed could be really beneficial in > some scenarios is another thing. > > This would also allow online defragmentation, together with access to > statistics, one that (for quick runs) has really good time/performance benefit > ratio. Agreed, I'm thinking of the online defragmentation based on hot access too. Btrfs usually has more fragment. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/