From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754179AbbDJVgd (ORCPT ); Fri, 10 Apr 2015 17:36:33 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50618 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbbDJVgb (ORCPT ); Fri, 10 Apr 2015 17:36:31 -0400 Date: Fri, 10 Apr 2015 14:36:29 -0700 From: Andrew Morton To: Andi Kleen Cc: mmarek@suse.cz, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Andi Kleen , hubicka@ucw.cz Subject: Re: [PATCH] lto: Add __noreorder and mark initcalls __noreorder Message-Id: <20150410143629.aaba355c08d3b71e5c1cddd0@linux-foundation.org> In-Reply-To: <20150408235023.GT2366@two.firstfloor.org> References: <1428499058-8322-1-git-send-email-andi@firstfloor.org> <20150408153112.bd375a883138f4c9fd319645@linux-foundation.org> <20150408235023.GT2366@two.firstfloor.org> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Apr 2015 01:50:23 +0200 Andi Kleen wrote: > > Head is spinning a bit. As this all appears to be shiny new > > added-by-andi gcc functionality, it would be useful if we could have a > > few more words describing what it's all about. Reordering of what with > > respect to what and why and why is it bad. Why is gcc reordering > > things anyway, and what's the downside of preventing this. Why is the > > compiler reordering things rather than the linker. etc etc etc. > > Ok, let me try. That was super-useful, thanks. I slurped it into the changelog - maybe one day it will provide material for Documentation/lto-stuff.txt. Big picture: do you have a feeling for how much benefit LTO will yield in the kernel, if/when it's all completed?