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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 2CF67C43441 for ; Tue, 13 Nov 2018 03:09:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8025223DD for ; Tue, 13 Nov 2018 03:09:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8025223DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fromorbit.com 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 S1730816AbeKMNFe (ORCPT ); Tue, 13 Nov 2018 08:05:34 -0500 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:57344 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbeKMNFe (ORCPT ); Tue, 13 Nov 2018 08:05:34 -0500 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail07.adl2.internode.on.net with ESMTP; 13 Nov 2018 13:39:27 +1030 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1gMP4w-0007nE-68; Tue, 13 Nov 2018 14:09:26 +1100 Date: Tue, 13 Nov 2018 14:09:26 +1100 From: Dave Chinner To: "Theodore Y. Ts'o" , Joe Perches , Eric Sandeen , "Darrick J. Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, LKML Subject: Re: [PATCH] xfs: Remove noinline from #define STATIC Message-ID: <20181113030926.GQ19305@dastard> References: <7302f4a13c1cbf62b07f636878ce25fcca84b6c4.camel@perches.com> <6420cf91-89c8-a876-7a0d-25ab8ba428b8@sandeen.net> <20181112214515.GN19305@dastard> <20181113011804.GP19305@dastard> <20181113015410.GB30750@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181113015410.GB30750@thunk.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 12, 2018 at 08:54:10PM -0500, Theodore Y. Ts'o wrote: > On Tue, Nov 13, 2018 at 12:18:05PM +1100, Dave Chinner wrote: > > I'm not interested in making code fast if distro support engineers > > can't debug problems on user systems easily. Optimising for > > performance over debuggability is a horrible trade off for us to > > make because it means users and distros end up much more reliant on > > single points of expertise for debugging problems. And that means > > the majority of the load of problem triage falls directly on very > > limited resources - the core XFS development team. A little bit of > > thought about how to make code easier to triage and debug goes a > > long, long way.... > > So at least in my experience, if the kernels are compiled with > CONFIG_DEBUG_INFO and/or CONFIG_DEBUG_INFO_REDUCED, > scripts/decode_stracktrace.sh seems to do a very nice job with inlined That doesn't help with kernel profiling and other such things that are based on callgraphs... > functions. Now, ext4 generally only has about 3 or 4 nested inlines, > and so I don't know how it works with 20 or 30 nested inlined > functions, so perhaps this is not applicable for XFS. > > But it perhaps toolchain technology has advanced since the Irix days > such that it's no longer as necessary to force the non-inlining of > functions for easing debugging? Not that I've noticed. Indeed, modern toolchains are moving the opposite direction - have you ever tried to debug a binary with gdb that was compiled with LTO enabled? Or maybe even just tried to profile it with perf? Cheers, Dave. -- Dave Chinner david@fromorbit.com