From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757281Ab0JRQyZ (ORCPT ); Mon, 18 Oct 2010 12:54:25 -0400 Received: from mga06.intel.com ([134.134.136.21]:60312 "EHLO orsmga101.jf.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751674Ab0JRQyZ convert rfc822-to-8bit (ORCPT ); Mon, 18 Oct 2010 12:54:25 -0400 MIME-Version: 1.0 In-Reply-To: <20101017185203.GD28060@infradead.org> References: <20101016065206.GO4681@dastard> <20101016192027.GA6883@infradead.org> <1287295077.3020.83.camel@localhost.localdomain> <1287313332.1998.172.camel@laptop> <1287323960.1998.360.camel@laptop> <20101017185203.GD28060@infradead.org> Date: Mon, 18 Oct 2010 09:44:47 -0700 Message-ID: Subject: Re: ima: use of radix tree cache indexing == massive waste of memory? From: Ryan Ware To: Christoph Hellwig Cc: Peter Zijlstra , Eric Paris , eparis@redhat.com, Mimi Zohar , Dave Chinner , linux-kernel@vger.kernel.org, Mimi Zohar , warthog9@kernel.org, hpa@zytor.com, devel@lists.fedoraprojet.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 17, 2010 at 11:52 AM, Christoph Hellwig wrote: > On Sun, Oct 17, 2010 at 03:59:20PM +0200, Peter Zijlstra wrote: >> Well, it does suck it needs to bloat data and code when its effectively >> disabled. Isn't there a way to gather this data before we enable it, eg. >> scan the files list on enable or somesuch? >> >> I mean, if you mandate an external storage you might as well extend >> struct inode, that's cheaper in each respect. > > That's in fact what it did initially.  While IBM claimed it would never > be enabled in distros and this would be fine I feared this would not be > true and told them to not make it have overhead if compiled in but not > used. Isn't it up to distros themselves to decide if this feature should be enabled? I bring this up because we are intending to include this turned on by default in the MeeGo kernel for the 1.2 release next year. I understand there are some technical concerns regarding performance. We should figure out how to resolve those. That said, upstream is the right place for this. Ryan > Turns out I wa right in my fear that IBM pressured distros to enable > it anyway.  And turns out that I should have verified they didn't > actually mess it up instead of expecting people to get such trivial > things right. > >> Me, I'm henceforth making sure to have CONFIG_IMA disabled... > > Yeah. > >> >  but it doesn't >> > help the fact that the suggested structure for storage (the radix >> > tree) is apparently quite inefficient.  I'd love to hear other >> > suggestions for a better structure.... >> >> radix tree is efficient for dense sets, not sparse sets. > > Which actually works just fine for inodes on many filesystems if you > use the right key. > -- > 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/ >