From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933839AbcHDPpq (ORCPT ); Thu, 4 Aug 2016 11:45:46 -0400 Received: from mout.kundenserver.de ([212.227.126.133]:65331 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756017AbcHDPow (ORCPT ); Thu, 4 Aug 2016 11:44:52 -0400 From: Arnd Bergmann To: Nicholas Piggin Cc: Stephen Rothwell , Nicolas Pitre , "linux-kernel@vger.kernel.org" , "Luis R. Rodriguez" , linux-next@vger.kernel.org, Paul Mackerras , Fengguang Wu , linuxppc-dev@lists.ozlabs.org, Guenter Roeck Subject: Re: powerpc allyesconfig / allmodconfig linux-next next-20160729 - next-20160729 build failures Date: Thu, 04 Aug 2016 17:43:20 +0200 Message-ID: <2145682.qktvngUhUu@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-31-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <20160804235418.1f235f55@roar.ozlabs.ibm.com> References: <20160804223139.0196b3aa@roar.ozlabs.ibm.com> <20160804235418.1f235f55@roar.ozlabs.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:Y8sMTm1ImKr+gDDenXRXjjmZmOJIjuWKgAS5yOj3siTmGwVsKBd y67GhH16gaCFIKVKrMOiJ2Q4ATWESYsSTN2LjmMcY4qa11fXvLB1NinpcWw7luyL6NrCD1e PBEiglVayxlppKqFoqYSQlEG5Wxodkm5Z4K02Nw0HwIMVI6xx9lwx2HwtRTg3I9pSxDrhOT aRxfFVDkx25mtfyz7wDBg== X-UI-Out-Filterresults: notjunk:1;V01:K0:MLzc0feK/Xg=:UyFzilS9DOnJnEgVO/qg8a PTApUxOHNCAgIYW2JTFj23h6ZkMnxbIpn6Al7ULswmS8BDPQOCADrIoE7MfC1ba06KETQmNb2 yOD+Szbihmz6HCFWxVR7p8tXbcsh4wFUXhETCNM+XXUYX+SGyo9Whj1R1yJP9hH/jpLc0pcEz rVdy3HOYwjOaEHGVTyQmOPbv4QWFaLkB+CYJ5lxFDVFbnbcHuOzLd+bHM9RGlLvqdd17pMcg8 sY/IDNstbj6DhwJ5TWb3b3OKDolJr30z/fP9D1bpSoO31Z2kRfMlHziWz2IwnAGWn9FaIQWTp KP36WoMSr4iJC13X+wvSjyiawXxMP+nkGE4B6f7j1nIbgL6KqWB41Zwuargyrzv3pyQ+abWXv wcU8cZnG1PYd1yGTKAC3d4HyC+ISLc/bNKjCtAOld1k5AmdZmjMhWw9gpqU/rbYoWW5rb4qKg 8p0D6sKVLlbDVVYhcnYWocfqiR9ucZ8dIaG6+8le4YPlzh60k2j+roxOaynDJ9y9Lc4E2hM4b 6NSzPYF7V8NbZLTQolPakSXJHTVa9vsi/OyzJfhzdmuxP9wDgi9SPtDCJjVDeXdE9wfsPKOul 5IlZ08hmlgcZ5V8sWdm7MdmM/L63ZUCm05iwu2UhUx/c+/7e9Xo/6AXBocN0uFZyiWo05qcUr HpQJWf3voO3BIlAm8bEo6TKQ0vqbyd0noz+QMgkJO+QZsy6dRP/Hab4/wQPm/M8u9IRLIp7X6 AjQRNhFPJfhF0QeC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, August 4, 2016 11:54:18 PM CEST Nicholas Piggin wrote: > On Thu, 4 Aug 2016 22:31:39 +1000 > Nicholas Piggin wrote: > > On Thu, 04 Aug 2016 14:09:02 +0200 > > Arnd Bergmann wrote: > > > Nicolas Pitre has done some related work, adding him to Cc. IIRC we have > > > actually had multiple implementations of -ffunction-sections/--gc-sections > > > in the past that people have used in production, but none of them > > > ever made it upstream. > > After some googling around it seems lto has been difficult to > get in and it was agreed this gc-sections should be done first > anyway (although it may indeed provide a superset of DCE, but > it's always going to be more costly and complicated). Lto would > have the same issue with liveness of entry points, which is > really the only thing you need change in the kernel as far as I > can see. Ok, good. > I didn't really see what problems people were having with it > though, so maybe it's architecture specific or something I > haven't run into yet. I remember trying it a few years ago without success, it's possible that old binutils versions were more problematic. I'm happy to test your patches on ARM, with my randconfig builder I tend to find obscure bugs in corner cases that you might not normally find with just defconfig/allmodconfig builds. Arnd