Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751311AbaG1R1q (ORCPT ); Mon, 28 Jul 2014 13:27:46 -0400 Received: from mail.kernel.org ([198.145.19.201]:37223 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751162AbaG1R1o (ORCPT ); Mon, 28 Jul 2014 13:27:44 -0400 Date: Mon, 28 Jul 2014 10:27:39 -0700 From: Alexei Starovoitov To: Linus Torvalds Cc: "Frank Ch. Eigler" , Markus Trippelsdorf , Steven Rostedt , Michel =?iso-8859-1?Q?D=E4nzer?= , Jakub Jelinek , Linux Kernel Mailing List , Debian GCC Maintainers , Debian Kernel Team Subject: Re: Random panic in load_balance() with 3.16-rc Message-ID: <20140728172737.GA17598@pg-vmw-gw1> References: <20140725140237.GB32669@home.goodmis.org> <20140726193557.GA21842@x4> <20140726201914.GB21842@x4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 On Mon, Jul 28, 2014 at 09:45:45AM -0700, Linus Torvalds wrote: > On Mon, Jul 28, 2014 at 5:26 AM, Frank Ch. Eigler wrote: > > > > Please note that the data produced by "-g -fvar-tracking" is consumed > > by tools like systemtap, perf, crash, and makes a significant > > difference to the observability of debug AND non-debug kernels. > > Yeah, and compared to having a buggy kernel, I care exactly this much: "". > > Besides, "significant difference" is very debatable indeed. It may be > noticeable, it's likely not actually significant. as far as I can see in gcc code, -fno-var-tracking-assignments is the main switch for 'vartrack' pass. So -fno-var-tracking-assignments is pretty much equivalent to -fno-var-tracking Both kill majority of debug info for local variables and function arguments. The end effect for perf/systemtap will be quite noticeable. It's not pretty, but adding it unconditionally was the right thing to do. Black listing compiler versions is too fragile. Look at the flip side: now size of build dir will be much smaller :) For gcc it's obviously a big blow. Now 10k lines pass developed over 10+ years will not be used :( -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/