From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756026AbaAII4x (ORCPT ); Thu, 9 Jan 2014 03:56:53 -0500 Received: from merlin.infradead.org ([205.233.59.134]:54094 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752319AbaAII4n (ORCPT ); Thu, 9 Jan 2014 03:56:43 -0500 Date: Thu, 9 Jan 2014 09:56:31 +0100 From: Peter Zijlstra To: Andi Kleen Cc: Sasha Levin , mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] lockdep: increase static allocations Message-ID: <20140109085631.GC7572@laptop.programming.kicks-ass.net> References: <1389208906-24338-1-git-send-email-sasha.levin@oracle.com> <87lhyq45go.fsf@tassilo.jf.intel.com> <52CDB0CF.5060904@oracle.com> <20140108232322.GH20765@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140108232322.GH20765@two.firstfloor.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 09, 2014 at 12:23:22AM +0100, Andi Kleen wrote: > On Wed, Jan 08, 2014 at 03:10:55PM -0500, Sasha Levin wrote: > > On 01/08/2014 02:51 PM, Andi Kleen wrote: > > >Sasha Levin writes: > > > > > >>Fuzzing a recent kernel with a large configuration hits the static > > >>allocation limits and disables lockdep. > > > > > >Doesn't that use a lot more memory? I thought lockdep preallocates. > > > > > >Doubling may be too aggressive. > > > > The patch adds about 4MB of memory usage, I didn't think it's too much for something > > that is only enabled during debugging. > > Wasting 4MB is an issue. > > Linus' first Linux system had less total memory than that. Meh.. if someone from the embedded people care we can add CONFIG_BASE_SMALL option, until then I couldn't care less about 4m. > > > > If this is an issue, can I suggest making these values configurable in the .config > > and just let users pick whatever they want? > > Better allocate it at boot time, using a boot parameter or somesuch. wrongbot andi is at it again.. no that's far too late.