Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757051AbZCUQeA (ORCPT ); Sat, 21 Mar 2009 12:34:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754698AbZCUQdv (ORCPT ); Sat, 21 Mar 2009 12:33:51 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:56426 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754630AbZCUQdu (ORCPT ); Sat, 21 Mar 2009 12:33:50 -0400 Date: Sat, 21 Mar 2009 17:33:28 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Anton Vorontsov , Steven Rostedt , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Fix TRACING_SUPPORT dependency Message-ID: <20090321163328.GH11183@elte.hu> References: <20090320150914.GA22769@oksana.dev.rtsoft.ru> <20090320190428.GD6224@elte.hu> <20090320193904.GA13707@oksana.dev.rtsoft.ru> <20090320195743.GA25147@elte.hu> <20090320202247.GA30654@oksana.dev.rtsoft.ru> <20090321161814.GC11183@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2550 Lines: 63 * Steven Rostedt wrote: > > On Sat, 21 Mar 2009, Ingo Molnar wrote: > > > > > * Anton Vorontsov wrote: > > > > > On Fri, Mar 20, 2009 at 08:57:43PM +0100, Ingo Molnar wrote: > > > > > > > > * Anton Vorontsov wrote: > > > > > > > > > On Fri, Mar 20, 2009 at 08:04:28PM +0100, Ingo Molnar wrote: > > > > > > > > > > > > * Anton Vorontsov wrote: > > > > > > > > > > > > > commit 40ada30f9621fbd831ac2437b9a2a399aad34b00 ("tracing: clean > > > > > > > up menu"), despite the "clean up" in its purpose, introduced > > > > > > > behavioural change for Kconfig symbols: we no longer able to > > > > > > > select tracing support on PPC32 (because IRQFLAGS_SUPPORT isn't > > > > > > > yet implemented). > > > > > > > > > > > > Could you please solve this by implementing proper > > > > > > irqflag-tracing support? It's been available upstream for almost > > > > > > three years. It's needed for lockdep support as well, etc. > > > > > > > > > > Breaking things via clean up patches is an interesting method of > > > > > encouraging something to implement. ;-) > > > > > > > > > > Surely I'll look into implementing irqflags tracing, but > > > > > considering that no one ever needed this for almost three years, > > > > > [...] > > > > > > > > Weird, there's no lockdep support? > > > > > > *ashamed*: apparently no such support currently exist for PPC32. ;-) > > > > Hm, do all the tracers even compile on ppc32 with your patch? > > > > We had periodic build failures on weird, unmaintained architectures > > that had no irqflags-tracing support and hence didnt know the > > raw_irqs_save/restore primitives ... > > > > I'm not trying to make things more difficult for you (and we can > > apply your patch if it builds fine and does not cause problems > > elsewhere), but there were some real downsides to not having proper > > irq APIs ... > > Note, the issue is not with the hooks into local_irq_save/restore, > but with the entry.S code. That code is very sensitive where the > irqs are enabled and disabled. i know. What i'm talking about is that non-lockdep architectures have the habit of not defining raw_local_irq_save() - which the tracing core relies on. Ingo -- 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/