From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 Date: Tue, 13 Nov 2018 14:09:26 +1100 From: Dave Chinner 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> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Theodore Y. Ts'o" , Joe Perches , Eric Sandeen , "Darrick J. Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, LKML 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