From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753784Ab0JTP0E (ORCPT ); Wed, 20 Oct 2010 11:26:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32318 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753500Ab0JTP0C (ORCPT ); Wed, 20 Oct 2010 11:26:02 -0400 Subject: Re: [PATCH 1/3] IMA: move read/write counters into struct inode From: Eric Paris To: Ingo Molnar Cc: Linus Torvalds , Al Viro , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, hch@infradead.org, zohar@us.ibm.com, warthog9@kernel.org, david@fromorbit.com, jmorris@namei.org, kyle@mcmartin.ca, hpa@zytor.com, akpm@linux-foundation.org In-Reply-To: <20101020151555.GC22271@elte.hu> References: <20101019011650.25346.99614.stgit@paris.rdu.redhat.com> <1287506215.2530.187.camel@localhost.localdomain> <20101019165530.GT19804@ZenIV.linux.org.uk> <1287528546.2530.277.camel@localhost.localdomain> <20101020143845.GB22271@elte.hu> <1287585996.2530.294.camel@localhost.localdomain> <20101020151555.GC22271@elte.hu> Content-Type: text/plain; charset="UTF-8" Date: Wed, 20 Oct 2010 11:25:35 -0400 Message-ID: <1287588335.2530.296.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2010-10-20 at 17:15 +0200, Ingo Molnar wrote: > * Eric Paris wrote: > > > On Wed, 2010-10-20 at 16:38 +0200, Ingo Molnar wrote: > > > * Eric Paris wrote: > > > > > > > Executive summary of the day's work: > > > > Yesterday morning: 944 bytes per inode in core > > > > Yesterday night: 24 bytes per inode in core > > > > Tonight: 4 bytes per inode in core. > > > > > > > > That's a x236 time reduction in memory usage. No I didn't even start looking > > > > at a freezer. Which could bring that 4 down to 0, but would add a scalability > > > > penalty on all inodes when IMA was enabled. > > > > > > Why not use inode->i_security intelligently? That already exists so that way > > > it's 0 bytes. > > > > > > Thanks, > > > > It still wouldn't be 0 bytes since there would be a 1-1 mapping from inode to > > i_security structs. [...] > > Only for IMA-affected files, right? No, we need to keep the open read counter even for non-IMA-affected files in case we later determine that it is IMA-affected. That's the 4 bytes I have today, which I said could be eliminated with a freezer that calculated it when IMA was enabled, but isn't something I'm looking at right now.... -Eric -Eric