From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758104AbYHTXXT (ORCPT ); Wed, 20 Aug 2008 19:23:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755115AbYHTXXK (ORCPT ); Wed, 20 Aug 2008 19:23:10 -0400 Received: from gw.goop.org ([64.81.55.164]:36469 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755034AbYHTXXJ (ORCPT ); Wed, 20 Aug 2008 19:23:09 -0400 Message-ID: <48ACA75A.9070306@goop.org> Date: Wed, 20 Aug 2008 16:23:06 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: "Alex Nixon (Intern)" CC: Yinghai Lu , Ingo Molnar , Linux Kernel Mailing List Subject: Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs References: <48AAFAE4.7070409@citrix.com> <86802c440808191044h74871ba1u62330dae18599436@mail.gmail.com> <0E902970173AF84089673FA54B7FE78A2CA11D@lonpexch01.citrite.net> In-Reply-To: <0E902970173AF84089673FA54B7FE78A2CA11D@lonpexch01.citrite.net> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alex Nixon (Intern) wrote: > I'm not sure about the general case, but Xen does not (Jeremy correct > me if I'm wrong). > No, no apics of any kind in the PV domU case. > Unless I'm missing something (which I may well be; I'm new to this > area of code), it seems more logical anyway to default back to the > calculated system-specific value (NR_IRQS), instead of 32, which seems > rather arbitrary. > I think the patch looks fine for now. But now that we seem to have unified the use of vectors (I haven't looked at the current code closely yet), I'd like to move Xen to mapping event channels -> vectors rather than IRQs, and have the per-cpu event channels share an irq. That will dramatically decrease the irq requirements for a PV domU (to 6 irqs + devices, rather than 6/cpu + devices; a typical domain may only need 10 irqs overall). J