From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756449AbYE0O4k (ORCPT ); Tue, 27 May 2008 10:56:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755790AbYE0O4c (ORCPT ); Tue, 27 May 2008 10:56:32 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:57492 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755660AbYE0O4b (ORCPT ); Tue, 27 May 2008 10:56:31 -0400 Date: Tue, 27 May 2008 16:56:06 +0200 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Thomas Gleixner , Linux Kernel Mailing List , Andi Kleen , Avi Kivity , "H. Peter Anvin" , "Eric W. Biederman" , Keir Fraser Subject: Re: Question about interrupt routing and irq allocation Message-ID: <20080527145606.GB24457@elte.hu> References: <483B34CA.8000600@goop.org> <20080527083729.GF29246@elte.hu> <483BD843.5080009@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <483BD843.5080009@goop.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jeremy Fitzhardinge wrote: >> So the most intelligent method would be to reserve the Linux irq >> itself but not the vector, i.e. allocate from irq_cfg[] in >> arch/x86/kernel/io_apic_64.c so that the irq number does not get >> reused - setting irq_cfg[irq].vector to -1 will achieve that. > > I'm initially targeting 32-bit, though obviously I'd like something > that works for both 32 and 64 bit. irq_cfg[] is missing in > io_apic_32.c; would I achieve the same effect by setting > irq_vector[irq] = 0xff or something? ok, here comes the next phase of a rather cunning plan: please unify these vector allocators first! ;-) it's nontrivial but would result in rather nice code. I dont know whether we want to extend per-CPU vectors to 32-bit as well ... but might be worth an attempt and we could give any exploratory patches a try in -tip. Eric, what do you think about the general approach? this would also pave the way towards unified APIC code. Hm? Ingo