Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757544AbYHSTAy (ORCPT ); Tue, 19 Aug 2008 15:00:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755344AbYHSTAq (ORCPT ); Tue, 19 Aug 2008 15:00:46 -0400 Received: from py-out-1112.google.com ([64.233.166.182]:32071 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755195AbYHSTAp (ORCPT ); Tue, 19 Aug 2008 15:00:45 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=Za8YP/gBEPlGefumODlNqNA1/nXvBCFnVuynhqdtNqdB2DVlHHLGMxpaIQKqYCnsTd pQFsNEKng0e/iAIVENtPnV0KyyuOTAImvsvJrluQMQVuNNWBqtIzfBO8mwE587GflqoN ZxXBlBzXwMXI8qtLf2bPOY0X+tt0UOKgUl9jk= Message-ID: <86802c440808191200u364ffd86h49af661e58d20ea3@mail.gmail.com> Date: Tue, 19 Aug 2008 12:00:43 -0700 From: "Yinghai Lu" To: "Alex Nixon" Subject: Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs Cc: "Ingo Molnar" , "Jeremy Fitzhardinge" , "Linux Kernel Mailing List" In-Reply-To: <48AB11A3.4060102@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <48AAFAE4.7070409@citrix.com> <86802c440808191044h74871ba1u62330dae18599436@mail.gmail.com> <0E902970173AF84089673FA54B7FE78A2CA11D@lonpexch01.citrite.net> <86802c440808191124v39ce2aa9rb548d3bdd75ca25c@mail.gmail.com> <48AB11A3.4060102@citrix.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1670 Lines: 48 On Tue, Aug 19, 2008 at 11:32 AM, Alex Nixon wrote: > Yinghai Lu wrote: >> >> On Tue, Aug 19, 2008 at 11:13 AM, Alex Nixon (Intern) >> wrote: >>> >>> Yinghai Lu wrote: >>>> >>>> On Tue, Aug 19, 2008 at 9:55 AM, Alex Nixon >>>> wrote: >>>>> >>>>> If the number of discovered IRQs is suspiciously low, this patch causes >>>>> the number reported to default to NR_IRQS, rather than 32. NR_IRQS has >>>>> already been defined to be a >sensible value for the current system (in >>>>> particular, at least 224 when paravirtualisation is involved). >>>>> >>>> if only one ioapic, nr will be 24<<1, you will get 48. Does pv has io >>>> apic >>>> ? >>>> >>>> YH >>>> >>> I'm not sure about the general case, but Xen does not (Jeremy correct me >>> if >>> I'm wrong). >>> >>> 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. >> >> can you try !CONFIG_HAVE_SPARSE_IRQ and CONFIG_HAVE_SPARSE_IRQ ? >> >> YH > > Sorry I should have mentioned originally - the bug occurs both with > CONFIG_HAVE_SPARSE_IRQ enabled, and disabled. maybe we need special probe_nr_irqs for PV or not call that in setup_arch for xen -- it will leave nr_irqs == NR_IRQS YH -- 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/