From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: Re: VFS hot tracking: How to calculate data temperature? Date: Fri, 2 Nov 2012 13:10:48 -0700 Message-ID: <20121102201048.GA20993@blackbox.djwong.org> References: <20121102084109.GA19753@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Zhi Yong Wu , linux-fsdevel@vger.kernel.org, linuxram@linux.vnet.ibm.com, Dave Chinner , cmm@us.ibm.com, Ben Chociej , James Northrup Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:40201 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750791Ab2KBULH (ORCPT ); Fri, 2 Nov 2012 16:11:07 -0400 Content-Disposition: inline In-Reply-To: <20121102084109.GA19753@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Nov 02, 2012 at 04:41:09PM +0800, Zheng Liu wrote: > On Fri, Nov 02, 2012 at 02:38:29PM +0800, Zhi Yong Wu wrote: > > Here also has another question. > > > > How to save the file temperature among the umount to be able to > > preserve the file tempreture after reboot? > > > > This above is the requirement from DB product. > > I thought that we can save file temperature in its inode struct, that > > is, add one new field in struct inode, then this info will be written > > to disk with inode. > > > > Any comments or ideas are appreciated, thanks. > > Hi Zhiyong, > > I think that we might define a callback function. If a filesystem wants > to save these data, it can implement a function to save them. The > filesystem can decide whether adding it or not by themselves. > > BTW, actually I don't really care about how to save these data because I > only want to observe which file is accessed in real time, which is very > useful for me to track a problem in our product system. I _think_ the vfs quota code simply asks the filesystem for a special inode where it save the quota data in whatever (FS-agnostic) format it wants. Have you considered something like that? (Or, maybe everyone secretly hates doing that? Secret files, yaaay...) --D > > Regards, > Zheng > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html