From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759300AbbCDLXW (ORCPT ); Wed, 4 Mar 2015 06:23:22 -0500 Received: from mail.skyhub.de ([78.46.96.112]:32914 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753545AbbCDLXV (ORCPT ); Wed, 4 Mar 2015 06:23:21 -0500 Date: Wed, 4 Mar 2015 12:22:06 +0100 From: Borislav Petkov To: Ingo Molnar Cc: x86-ml , Peter Zijlstra , Arnaldo Carvalho de Melo , Andy Lutomirski , lkml , Linus Torvalds Subject: Re: [GIT PULL] x86/alternatives padding Message-ID: <20150304112206.GB3516@pd.tnic> References: <20150303170632.GE25768@pd.tnic> <20150304073221.GD22014@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150304073221.GD22014@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 04, 2015 at 08:32:21AM +0100, Ingo Molnar wrote: > Just curious: did the kernel image size change before/after these > changes? I.e. was any of the existing alternative instructions using > sites coded sub-optimally, with a larger maximum instruction size > allocated than strictly needed? > > At least some of your improvements made things more optimal - > wondering at the total win, beyond the significant maintainability win > that is. Well, kernel image doesn't change while vmlinux shows only a very small .text increase of about 2K. I'm not sure yet why that happens though because it shouldn't be the padding. Because we will have to do it anyway, this patchset makes it automatic instead of by-hand, so to speak. Let me bisect it and see which patch adds the increase. 4.0-rc1 with alternatives patchset: =================================== Setup is 15644 bytes (padded to 15872 bytes). System is 5855 kB CRC f2669897 Kernel: arch/x86/boot/bzImage is ready (#1) text data bss dec hex filename 12292971 1595264 1085440 14973675 e47aeb vmlinux plain 4.0-rc1: ============== Setup is 15644 bytes (padded to 15872 bytes). System is 5855 kB CRC 7200607a Kernel: arch/x86/boot/bzImage is ready (#1) text data bss dec hex filename 12290539 1595264 1085440 14971243 e4716b vmlinux -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --