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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D32FC7EE2E for ; Fri, 26 May 2023 02:28:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233393AbjEZC2z (ORCPT ); Thu, 25 May 2023 22:28:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233494AbjEZC2y (ORCPT ); Thu, 25 May 2023 22:28:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B536E13D; Thu, 25 May 2023 19:28:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 40E8A64C5C; Fri, 26 May 2023 02:28:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15528C433D2; Fri, 26 May 2023 02:28:47 +0000 (UTC) Date: Thu, 25 May 2023 22:28:44 -0400 From: Steven Rostedt To: Nadav Amit Cc: "Arnd Bergmann" , "Thomas Gleixner" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-um@lists.infradead.org, Linux-Arch , linux-mm@kvack.org, "Andy Lutomirski" , "Ingo Molnar" , "Dave Hansen" , "Borislav Petkov" , x86@kernel.org, Peter Zijlstra , Nadav Amit Subject: Re: [PATCH v2 2/3] compiler: inline does not imply notrace Message-ID: <20230525222844.6a0d84f8@rorschach.local.home> In-Reply-To: <20230525210040.3637-3-namit@vmware.com> References: <20230525210040.3637-1-namit@vmware.com> <20230525210040.3637-3-namit@vmware.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Thu, 25 May 2023 14:00:39 -0700 Nadav Amit wrote: > From: Nadav Amit > > Functions that are marked as "inline" are currently also not tracable. > This limits tracing functionality for many functions for no reason. > Apparently, this has been done for two reasons. > > First, as described in commit 5963e317b1e9d2a ("ftrace/x86: Do not > change stacks in DEBUG when calling lockdep"), it was intended to > prevent some functions that cannot be traced from being traced as these > functions were marked as inline (among others). > > Yet, this change has been done a decade ago, and according to Steven > Rostedt, ftrace should have improved and hopefully resolved nested > tracing issues by now. Arguably, if functions that should be traced - > for instance since they are used during tracing - still exist, they > should be marked as notrace explicitly. > > The second reason, which Steven raised, is that attaching "notrace" to > "inline" prevented tracing differences between different configs, which > caused various problem. This consideration is not very strong, and tying > "inline" and "notrace" does not seem very beneficial. The "inline" > keyword is just a hint, and many functions are currently not tracable > due to this reason. > > Disconnect "inline" from "notrace". FYI, I have a patch queued (still needs to go through testing) that already does this ;-) https://lore.kernel.org/all/20230502164102.1a51cdb4@gandalf.local.home/ -- Steve