Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751103AbWABWX5 (ORCPT ); Mon, 2 Jan 2006 17:23:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751109AbWABWX5 (ORCPT ); Mon, 2 Jan 2006 17:23:57 -0500 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:11537 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S1751103AbWABWX4 (ORCPT ); Mon, 2 Jan 2006 17:23:56 -0500 Date: Mon, 2 Jan 2006 22:23:35 +0000 From: Russell King To: Arjan van de Ven Cc: Krzysztof Halasa , Ingo Molnar , Adrian Bunk , Tim Schmielau , Linus Torvalds , Dave Jones , Andrew Morton , lkml , mpm@selenic.com Subject: Re: [patch 00/2] improve .text size on gcc 4.0 and newer compilers Message-ID: <20060102222335.GB5412@flint.arm.linux.org.uk> Mail-Followup-To: Arjan van de Ven , Krzysztof Halasa , Ingo Molnar , Adrian Bunk , Tim Schmielau , Linus Torvalds , Dave Jones , Andrew Morton , lkml , mpm@selenic.com References: <20051230074916.GC25637@elte.hu> <20051231143800.GJ3811@stusta.de> <20051231144534.GA5826@elte.hu> <20051231150831.GL3811@stusta.de> <20060102103721.GA8701@elte.hu> <1136198902.2936.20.camel@laptopd505.fenrus.org> <20060102134345.GD17398@stusta.de> <20060102140511.GA2968@elte.hu> <1136227893.2936.51.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1136227893.2936.51.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1863 Lines: 65 On Mon, Jan 02, 2006 at 07:51:32PM +0100, Arjan van de Ven wrote: > On Mon, 2006-01-02 at 19:44 +0100, Krzysztof Halasa wrote: > > Ingo Molnar writes: > > > > > what is the 'deeper problem'? I believe it is a combination of two > > > (well-known) things: > > > > > > 1) people add 'inline' too easily > > > 2) we default to 'always inline' > > > > For example, I add "inline" for static functions which are only called > > from one place. > > you know what? gcc inlines those automatic even without you typing > "inline". (esp if you have unit-at-a-time enabled) Rubbish it will. static void fn1(void *f) { } void fn2(void *f) { fn1(f); } on ARM produces: .text .align 2 .type fn1, %function fn1: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. @ lr needed for prologue mov pc, lr .size fn1, .-fn1 .align 2 .global fn2 .type fn2, %function fn2: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. @ lr needed for prologue b fn1 .size fn2, .-fn2 .ident "GCC: (GNU) 3.3 20030728 (Red Hat Linux 3.3-16)" You can't get a simpler function than fn1 to automatically inline. GCC will only automatically inline using -O3. We don't use -O3 with the kernel - only -O2 and -Os. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - 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/