Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753658AbbKWRF0 (ORCPT ); Mon, 23 Nov 2015 12:05:26 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:33127 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750976AbbKWRFY (ORCPT ); Mon, 23 Nov 2015 12:05:24 -0500 Date: Mon, 23 Nov 2015 18:04:56 +0100 From: Willy Tarreau To: Arnd Bergmann Cc: Russell King - ARM Linux , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, josh@joshtriplett.org Subject: Re: [RFC] asm-generic: default BUG_ON(x) to "if(x) BUG()" Message-ID: <20151123170456.GE768@1wt.eu> References: <5868782.RxZY0W5S4d@wuerfel> <20151123163359.GC768@1wt.eu> <20151123163750.GT8644@n2100.arm.linux.org.uk> <4150271.zrLzq08T60@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4150271.zrLzq08T60@wuerfel> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1729 Lines: 35 On Mon, Nov 23, 2015 at 05:52:38PM +0100, Arnd Bergmann wrote: > On Monday 23 November 2015 16:37:50 Russell King - ARM Linux wrote: > > On Mon, Nov 23, 2015 at 05:33:59PM +0100, Willy Tarreau wrote: > > > I think you could do better by simply calling panic("BUG!") instead as > > > BUG() does. It will avoid the printk() call and pushing the file/line > > > number onto the stack. It will also probably not inflate the rodata this > > > way. > > > > Does that not depend on the architectures BUG() implementation? If an > > architecture implements it as a signalling illegal instruction and a > > lookup table, changing it to be a panic() would probably be more code. > > Correct, overall, we are down to a 1.40% size reduction compared to > 1.70% without my patch and 1.49% with my version: > > section CONFIG_BUG=y CONFIG_BUG=n CONFIG_BUG=n+patch panic("BUG!") > > .text 8320248 | 8180944 | 8207688 | 8221848 > .rodata 3633720 | 3567144 | 3570648 | 3567344 > __bug_table 32508 | --- | --- | --- > __modver 692 | 1584 | 2176 | 1384 > .init.text 558132 | 548300 | 550088 | 550592 > .exit.text 12380 | 12256 | 12380 | 12448 > .data 1016672 | 1016064 | 1016128 | 1016064 > Total 14622556 | 14374510 | 14407326 | 14417898 Thanks for testing :-) Willy -- 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/