Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752717AbZKTKwF (ORCPT ); Fri, 20 Nov 2009 05:52:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752243AbZKTKwE (ORCPT ); Fri, 20 Nov 2009 05:52:04 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:36018 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751887AbZKTKwD (ORCPT ); Fri, 20 Nov 2009 05:52:03 -0500 Date: Fri, 20 Nov 2009 11:51:54 +0100 From: Ingo Molnar To: Christoph Hellwig Cc: "Kok, Auke" , "Frank Ch. Eigler" , Arjan van de Ven , Jeff Garzik , "Wu, Fengguang" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , Al Viro , Frederic Weisbecker Subject: Re: [PATCH] vfs: Add a trace point in the mark_inode_dirty function Message-ID: <20091120105154.GB12634@elte.hu> References: <20091025225342.007138f5@infradead.org> <20091111020108.GA11423@localhost> <20091110223456.01ef355f@infradead.org> <4AFA6AEF.5060306@garzik.org> <20091111081905.270a4e55@infradead.org> <4AFB4AC7.1090405@intel.com> <20091112072217.GA31719@elte.hu> <20091120104335.GB29143@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091120104335.GB29143@infradead.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1540 Lines: 36 * Christoph Hellwig wrote: > Guys, I think both the inode number and name do have a use case. For > file system developers observing the filesystem the inode number is > very useful, and if you look at the ext4 tracing already in tree or > the xfs tracing going in in the next window they use the inode number > all over. > > Which btw brings up another good argument - to make the tracing really > useful we need to have conventions. While the inode number seems to > be a realtively easy one printing the device is more difficult. XFS > just prints the raw major/minor to stay simple, ext4 has a complicated > ad-hoc cache of device names, and this one just prints the superblock > id string. Agreed. > Of course for a user the name is a lot more meaninful, but also > relatively expensive to generate. Then again I'm not even sure how > the last pathname component only here is all that useful - it can't be > used to easily find the file. That's not the main point though - the point is for app developers (and users) being able to see 'oh, _that_ file it is, we need to fix that'. In the context of a specific app, the last component filename carries 95% of the useful information. Look at how PowerTOP does it, for a real-life usecase. Ingo -- 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/