From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Piggin Subject: Re: [PATCH 1/5] kbuild: allow architectures to use thin archives instead of ld -r Date: Mon, 8 Aug 2016 13:25:32 +1000 Message-ID: <20160808132532.3ce8c0b6@roar.ozlabs.ibm.com> References: <1470399123-8455-1-git-send-email-npiggin@gmail.com> <1470399123-8455-2-git-send-email-npiggin@gmail.com> <20160806201045.GA25821@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f67.google.com ([209.85.220.67]:34344 "EHLO mail-pa0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997AbcHHDZn (ORCPT ); Sun, 7 Aug 2016 23:25:43 -0400 In-Reply-To: <20160806201045.GA25821@ravnborg.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Sam Ravnborg Cc: linux-kbuild@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Stephen Rothwell , Arnd Bergmann , Nicolas Pitre , Segher Boessenkool , Alan Modra On Sat, 6 Aug 2016 22:10:45 +0200 Sam Ravnborg wrote: > Hi Nicholas. > > On Fri, Aug 05, 2016 at 10:11:59PM +1000, Nicholas Piggin wrote: > > From: Stephen Rothwell > > > > ld -r is an incremental link used to create built-in.o files in build > > subdirectories. It produces relocatable object files containing all > > its input files, and these are are then pulled together and relocated > > in the final link. Aside from the bloat, this constrains the final > > link relocations, which has bitten large powerpc builds with > > unresolvable relocations in the final link. > > > > Alan Modra has recommended the kernel use thin archives for linking. > > This is an alternative and means that the linker has more information > > available to it when it links the kernel. > > > > This patch enables a config option architectures can select, > If we want to do this, then I suggest to make the logic reverse. > Architectures that for some reasons cannot use this should > have the possibility to avoid it. But let it be enabled by default. I was thinking the build matrix (architectures x build options x toolchains) is a bit too large to switch it for everybody. I've far from even tested it for a fraction of powerpc builds. I would prefer arch maintainers to switch it themselves, but I do hope we can move everybody and just remove the old method within a few releases. But I'm happy to go with whatever arch and kbuild maintainers prefer, so I appreciate any discussion on it. Thanks, Nick