From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753648Ab3LSPt4 (ORCPT ); Thu, 19 Dec 2013 10:49:56 -0500 Received: from mail-ea0-f170.google.com ([209.85.215.170]:34205 "EHLO mail-ea0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752165Ab3LSPty (ORCPT ); Thu, 19 Dec 2013 10:49:54 -0500 Date: Thu, 19 Dec 2013 16:49:51 +0100 From: Ingo Molnar To: Peter Zijlstra Cc: Sasha Levin , LKML , Dave Jones Subject: Re: lockdep: BUG: MAX_LOCKDEP_ENTRIES too low! Message-ID: <20131219154951.GB24658@gmail.com> References: <52B289F4.7060205@oracle.com> <20131219103401.GE30183@twins.programming.kicks-ass.net> <52B2FC66.9010309@oracle.com> <20131219152002.GK16438@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131219152002.GK16438@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > On Thu, Dec 19, 2013 at 09:02:14AM -0500, Sasha Levin wrote: > > On 12/19/2013 05:34 AM, Peter Zijlstra wrote: > > >On Thu, Dec 19, 2013 at 12:53:56AM -0500, Sasha Levin wrote: > > >>Hi all, > > >> > > >>I think that my bloated kernel managed to create way too many entries in the > > >>dependency table. If that sounds right, I can send a patch to increase those. > > >> > > >>Attached /proc/lock_stat as requested as well. > > > > > >/proc/lockdep_stats not lock_stat :-) > > > > > >Do you still happen to have that? > > > > Is the BUG message intentional ("Please attach the output of /proc/lock_stat to the bug report")? > > It does? This happened when I wasn't looking.. > > Commit 199e371f59d31 did that; and the Changelog fails to mention why or > what. Ingo, Dave? Simple oversight I think, should be fixed. > [...] > > One might argue that the validator should be modified to allow lock > classes to be reused. However, if you are tempted to make this > argument, first review the code and think through the changes that > would be required, keeping in mind that the lock classes to be > removed are likely to be linked into the lock-dependency graph. > This turns out to be harder to do than to say. Yes, an append-only data structure was a conscious simplification I decided on very early. (It also increases general robustness if your data structure can never go away.) Thanks, Ingo