From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F34F3C4321E for ; Fri, 7 Sep 2018 13:53:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A55482077C for ; Fri, 7 Sep 2018 13:53:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A55482077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729211AbeIGSev (ORCPT ); Fri, 7 Sep 2018 14:34:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:45776 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728205AbeIGSev (ORCPT ); Fri, 7 Sep 2018 14:34:51 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 601982075E; Fri, 7 Sep 2018 13:53:46 +0000 (UTC) Date: Fri, 7 Sep 2018 09:53:44 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Petr Mladek , Sergey Senozhatsky , LKML , Ingo Molnar , Thomas Gleixner , Sergey Senozhatsky , "Paul E. McKenney" Subject: Re: [PATCH] printk/tracing: Do not trace printk_nmi_enter() Message-ID: <20180907095344.75465afd@gandalf.local.home> In-Reply-To: <20180907093055.GL24082@hirez.programming.kicks-ass.net> References: <20180905213334.03375777@vmware.local.home> <20180906023151.GA749@jagdpanzerIV> <20180907074531.GM24106@hirez.programming.kicks-ass.net> <20180907082834.vjycyvt6nddpb4la@pathway.suse.cz> <20180907093055.GL24082@hirez.programming.kicks-ass.net> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 7 Sep 2018 11:30:55 +0200 Peter Zijlstra wrote: > > That said, I am not against this change. Especially the inlining > > is a good move. Note that lockdep_off()/lockdep_on() must not > > be traced as well. > > Hard to trace an inline funcion; we could make it __always_inline to > feel better. In the old days, you would need to make it __always_inline, because if gcc didn't inline it (and it did so in the past), it would be traced and would re-introduce this bug. But I've hit this issue too many times in the past, that I added "notrace" to the "inline" definition, where all "inline" labeled functions are also "notrace". lockdep.o has the -pg option removed in the Makefile so that all functions in lockdep.c is notrace, which is why it was fine to keep it there. But adding __always_inline may not be a bad idea regardless. -- Steve