Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753772Ab2FZUeI (ORCPT ); Tue, 26 Jun 2012 16:34:08 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39344 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751565Ab2FZUeH (ORCPT ); Tue, 26 Jun 2012 16:34:07 -0400 Date: Tue, 26 Jun 2012 22:34:00 +0200 From: Andi Kleen To: Mel Gorman Cc: Andi Kleen , Rafael Aquini , linux-mm@kvack.org, Rik van Riel , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH 1/4] mm: introduce compaction and migration for virtio ballooned pages Message-ID: <20120626203400.GA11413@one.firstfloor.org> References: <7f83427b3894af7969c67acc0f27ab5aa68b4279.1340665087.git.aquini@redhat.com> <20120626101729.GF8103@csn.ul.ie> <20120626165258.GY11413@one.firstfloor.org> <20120626201513.GJ8103@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120626201513.GJ8103@csn.ul.ie> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 969 Lines: 25 > How is the compiler meant to optimise away "cond" if it's a function > call? Inlines can be optimized away. These tests are usually inlines. > What did I miss? If nothing, then I will revert this particular change > and Rafael will need to be sure his patch is not using VM_BUG_ON to call > a function with side-effects. Do you have an example where the code is actually different, or are you just speculating? FWIW for my config both generates the same code: size vmlinux-andi-vmbug vmlinux-vmbug-nothing text data bss dec hex filename 11809704 1457352 1159168 14426224 dc2070 vmlinux-andi-vmbug 11809704 1457352 1159168 14426224 dc2070 vmlinux-vmbug-nothing -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/