From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759987AbcIWOF1 (ORCPT ); Fri, 23 Sep 2016 10:05:27 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:33315 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759913AbcIWOFW (ORCPT ); Fri, 23 Sep 2016 10:05:22 -0400 Subject: Re: [PATCH 0/2] Ajust lockdep static allocations To: Peter Zijlstra References: <1474569816-170269-1-git-send-email-babu.moger@oracle.com> <20160923071246.GJ2794@worktop> Cc: mingo@redhat.com, akpm@linux-foundation.org, keescook@chromium.org, dan.j.williams@intel.com, aryabinin@virtuozzo.com, tj@kernel.org, linux-kernel@vger.kernel.org From: Babu Moger Organization: Oracle Corporation Message-ID: Date: Fri, 23 Sep 2016 09:04:42 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160923071246.GJ2794@worktop> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/23/2016 2:12 AM, Peter Zijlstra wrote: > On Thu, Sep 22, 2016 at 11:43:34AM -0700, Babu Moger wrote: >> These patches adjust the static allocations for lockdep >> data structures used for debugging locking correctness. The current >> code reserves about 4MB extra space for these data structures. Most >> of the configurations do not need these many data structures. While >> testing, I have not seen it go beyond 20% of already reserved entries. >> >> $grep "lock-classes" /proc/lockdep_stats >> lock-classes: 1560 [max: 8191] >> >> Reserving even more space seems unreasonable. So, keeping the default >> entries small as before the Commit 1413c0389333 ("lockdep: Increase static >> allocations"). Added new CONFIG_PROVE_LOCKING_PLUS in case someone >> needs more entries to debug their large configuration. > Why make this more complicated? There's absolutely no upside to this > change as far as I can see. Peter, What do you mean? Revert the commit 1413c038933? Right now, I cannot boot my setup after enabling lockdep. How do you think we can handle this?