From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759519AbcIWT6U (ORCPT ); Fri, 23 Sep 2016 15:58:20 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:26698 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756741AbcIWT6T (ORCPT ); Fri, 23 Sep 2016 15:58:19 -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> <20160923143413.GM5008@twins.programming.kicks-ass.net> <71daf047-059d-3478-9e08-989d44211a9c@oracle.com> <20160923150439.GD5012@twins.programming.kicks-ass.net> <842fdad9-638e-f98c-5e3d-c3e698943e30@oracle.com> <20160923154041.GO5008@twins.programming.kicks-ass.net> 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, Rob Gardner , davem@davemloft.net From: Babu Moger Organization: Oracle Corporation Message-ID: Date: Fri, 23 Sep 2016 14:57:39 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20160923154041.GO5008@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/23/2016 10:40 AM, Peter Zijlstra wrote: > On Fri, Sep 23, 2016 at 10:15:46AM -0500, Babu Moger wrote: > >>>> Correct, We can't boot with lockdep. Sorry I did not make that clear. >>>> We have a limit on static size of the kernel. >>> This stuff should be in .bss not .data. It should not affect the static >>> size at all. Or am I misunderstanding things? >> Here it is. >> $ ./scripts/bloat-o-meter vmlinux.lockdep.small vmlinux.lockdep.big > What does bloat-o-meter have to do with things? The static image size is > not dependent on .bss, right? Peter, We checked again. Yes, It goes in .bss section. But in sparc we have to fit .text, .data, .bss in 7 permanent TLBs(that is totally 28MB). It was fine so far. But the commit 1413c0389333 ("lockdep: Increase static allocations") added extra 4MB which makes it go beyond 28MB. That is causing system boot up problems in sparc. Yes. We know it. This is a limitation. Changing this limit in our hardware is a much bigger change which we cannot address right away. So, we are trying to come up with a solution which can work for all. I will re-post the patches with CONFIG_BASE_SMALL option if there is no objections. CCing David Miller and Rob Gardner. They might be able to explain more if you have any more questions. Here is the discussion thread if you guys want to look at history. https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1237642.html