Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268982AbUIQVHK (ORCPT ); Fri, 17 Sep 2004 17:07:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269022AbUIQVDG (ORCPT ); Fri, 17 Sep 2004 17:03:06 -0400 Received: from mail-relay-2.tiscali.it ([213.205.33.42]:8677 "EHLO mail-relay-2.tiscali.it") by vger.kernel.org with ESMTP id S269001AbUIQU6o (ORCPT ); Fri, 17 Sep 2004 16:58:44 -0400 Date: Fri, 17 Sep 2004 22:56:39 +0200 From: Andrea Arcangeli To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Andrew Morton , Linus Torvalds , William Lee Irwin III , Arjan van de Ven , Lee Revell Subject: Re: [patch] remove the BKL (Big Kernel Lock), this time for real Message-ID: <20040917205639.GB15426@dualathlon.random> References: <20040915151815.GA30138@elte.hu> <20040917103945.GA19861@elte.hu> <20040917125334.GA4954@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040917125334.GA4954@elte.hu> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1599 Lines: 31 On Fri, Sep 17, 2004 at 02:53:34PM +0200, Ingo Molnar wrote: > the attached debug patch is ontop of the above patch and prints warnings > if code uses smp_processor_id() in a preemptible section of code. The > patch gets rid of a number of common false positives but more false > positives are more than likely. This cannot be applied to 2.6 IMHO. it still doesn't track the lock_kernel usage inside a spinlock, and even if it did, we cannot use the stable 2.6 userbase for the beta testing and see if some production machine triggers those warnings. If you would make this a config option *then* it could be included, OTOH for these kind of things 2.7 would be more appropriate (the config option is just a waste of resources since eventually the whole thing will go away). Overall I think this is not a change that a vendor kernel could ever make in the middle of a stable series (it sounds quite similar to preempt, even if less risky, and it really buys nothing to the end user and in turn it's definitely not justified), and in turn I don't think it's appropriate for a 2.6 mainline either (at least by default without config option like you're posting). Infact I'm not even convinced this is the right step forward in the removal of the BKL, rather than wasting our time discussing this, it'd be better to start removing the lock_kernel calls. - 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/