From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932233Ab0JRPJ3 (ORCPT ); Mon, 18 Oct 2010 11:09:29 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:53469 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756159Ab0JRPJ2 (ORCPT ); Mon, 18 Oct 2010 11:09:28 -0400 Date: Mon, 18 Oct 2010 11:09:20 -0400 From: Christoph Hellwig To: Eric Paris Cc: "Ted Ts'o" , Peter Zijlstra , Eric Paris , Mimi Zohar , Christoph Hellwig , Dave Chinner , linux-kernel@vger.kernel.org, Mimi Zohar , warthog9@kernel.org, hpa@zytor.com Subject: Re: ima: use of radix tree cache indexing == massive waste of memory? Message-ID: <20101018150920.GA24907@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > It can be turned on any time inside the initrd without loss of integrity > assuming the kernel and initrd were both measured and stored in a TPM > PCR. I'm willing to agree that the usefulness might be limited, but it > isn't non-existant. I'm going to make a note to look at other ways to > cut down the memory usage. It's not just memory overhead - it also adds another global reasource and global lock for every inode allocation/freeing. That's okay if people actually want to use IMA - but if you do it everywhere it's a real PITA. If there's seriously no way to fix it up to not cause harm by default just extending the inode is the much better way to go. But given that it's already in distros with a kABI I suspect some people will be interested in fixing it for people instead of forcing this overhead on their customers for years. We might want to just piggyback on that.