Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264322AbUANWYK (ORCPT ); Wed, 14 Jan 2004 17:24:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264398AbUANWYJ (ORCPT ); Wed, 14 Jan 2004 17:24:09 -0500 Received: from modemcable178.89-70-69.mc.videotron.ca ([69.70.89.178]:63360 "EHLO montezuma.fsmlabs.com") by vger.kernel.org with ESMTP id S264322AbUANWX4 (ORCPT ); Wed, 14 Jan 2004 17:23:56 -0500 Date: Wed, 14 Jan 2004 17:22:37 -0500 (EST) From: Zwane Mwaikambo To: James Cleverdon cc: Andrew Morton , Linux Kernel , Linus Torvalds , Chris McDermott , "Martin J. Bligh" Subject: Re: [PATCH] 2.6.1-mm2: Get irq_vector size right for generic subarch UP installer kernels In-Reply-To: <200401141159.03248.jamesclv@us.ibm.com> Message-ID: References: <200401131627.02138.jamesclv@us.ibm.com> <200401141159.03248.jamesclv@us.ibm.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: 1452 Lines: 31 On Wed, 14 Jan 2004, James Cleverdon wrote: > On Tuesday 13 January 2004 5:00 pm, Zwane Mwaikambo wrote: > > On Tue, 13 Jan 2004, James Cleverdon wrote: > > > Problem: Earlier I didn't consider the case of the generic sub-arch and > > > uni-proc installer kernels used by a number of distros. It currently is > > > scaled by NR_CPUS. The correct values should be big for summit and > > > generic, and can stay the same for all others. > > > > This all looks strange, especially in assign_irq_vector() does this > > mean that you'll try and allocate up to 1024 vectors? > > The irq_vector array name is a bit misleading. It contains the vectors for > each potential I/O APIC RTE. The array needs to be at least the sum of all > the RTEs in the system. Summit PCI bridge chips have large I/O APICs (50 > RTEs), and a large system has up to 16 of them. 16*50 = 800. Allocating 1k > entries provides a pad for the future, and u8 doesn't cost much. Ok i understand the need to accomodate all the RTEs, but what i was considering was what happens when assign_irq_vector runs out of vectors to allocate and ends up "wrapping". I just sent an email to Jun Nakajima with a bit more detail. Thanks, Zwane - 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/