Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750868AbVKMTZT (ORCPT ); Sun, 13 Nov 2005 14:25:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750862AbVKMTZT (ORCPT ); Sun, 13 Nov 2005 14:25:19 -0500 Received: from smtp.osdl.org ([65.172.181.4]:54414 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1750835AbVKMTZS (ORCPT ); Sun, 13 Nov 2005 14:25:18 -0500 Date: Sun, 13 Nov 2005 11:24:31 -0800 (PST) From: Linus Torvalds To: Dave Jones cc: Zachary Amsden , Pavel Machek , Andrew Morton , Linux Kernel Mailing List , "H. Peter Anvin" , Zwane Mwaikambo , Pratap Subrahmanyam , Christopher Li , "Eric W. Biederman" , Ingo Molnar Subject: Re: [PATCH 1/10] Cr4 is valid on some 486s In-Reply-To: <20051113074241.GA29796@redhat.com> Message-ID: References: <200511100032.jAA0WgUq027712@zach-dev.vmware.com> <20051111103605.GC27805@elf.ucw.cz> <4374F2D5.7010106@vmware.com> <4374FB89.6000304@vmware.com> <20051113074241.GA29796@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1004 Lines: 25 On Sun, 13 Nov 2005, Dave Jones wrote: > > Looks like the Ubuntu people already did this... Yeah, that looks like a sane patch, although I dislike the #ifdef config option thing (either it works or it doesn't). It also does it the right way: using LOCK_PREFIX means that you catch exactly the users that depend on SMP, and not _all_ "lock" prefixes (as mentioned, some of the lock prefixes are there as memory fences and are valid and needed even on UP). So me likee. The only question being whether you'd actually want to nop out the spinlock instructions _entirely_ (in addition to changing the nops on things like semaphores). Without the lock, they're not that expensive, but hey, it's still a useless (memory-modifying) instruction. Linus - 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/