From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: Regression: Bisected, IRQ and MSI allocations screwed without sparse irq Date: Fri, 21 Nov 2008 11:33:34 +0100 Message-ID: <1227263614.25811.25.camel@localhost.localdomain> References: <1226572171.6834.87.camel@localhost.localdomain> <20081113.141513.116537651.davem@davemloft.net> <20081119.151138.93409143.davem@davemloft.net> Reply-To: jdb@comx.dk Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Jesper Dangaard Brouer , David Miller , netdev , LKML , Robert Olsson To: Thomas Gleixner Return-path: Received: from lanfw001a.cxnet.dk ([87.72.215.196]:39941 "EHLO lanfw001a.cxnet.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753235AbYKUKdi (ORCPT ); Fri, 21 Nov 2008 05:33:38 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2008-11-20 at 16:34 -0800, Thomas Gleixner wrote: > On Thu, 20 Nov 2008, Jesper Dangaard Brouer wrote: > > I have bisected a regression to your commit > > 3235e936c0cc3589309280b6f59e5096779adae3, > > "x86: remove sparse irq from Kconfig". > > > > Its actually not necessary your fault, as your commit simply removes > > the config option HAVE_SPARSE_IRQ. This revels the bug / regression > > I'm exposted to. > > Yup, the bisect result is pretty useless. > > > The cause of this problem (tracked down together with Robert Olsson) > > is that on 2.6.28 I have a lot less IRQs available. It seems max 34 > > IRQs. Due the reduced number of IRQs the NIU driver cannot get > > enough IRQs to the interfaces, and starts to use "IO-APIC" based > > IRQs. > > Can you please try the attached patch ? I have tried the patch and it solved the problem! :-) I'll gladly test other patches from your. Guess this patch needs to be brushed up before a mainline patch is ready. My hardware is a HP ProLiant DL380-G5. > ----- > arch/x86/kernel/io_apic.c | 22 +--------------------- > 1 file changed, 1 insertion(+), 21 deletions(-) > > Index: linux-2.6/arch/x86/kernel/io_apic.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/io_apic.c > +++ linux-2.6/arch/x86/kernel/io_apic.c > @@ -3594,27 +3594,7 @@ int __init io_apic_get_redir_entries (in > > int __init probe_nr_irqs(void) > { > - int idx; > - int nr = 0; > -#ifndef CONFIG_XEN > - int nr_min = 32; > -#else > - int nr_min = NR_IRQS; > -#endif > - > - for (idx = 0; idx < nr_ioapics; idx++) > - nr += io_apic_get_redir_entries(idx) + 1; > - > - /* double it for hotplug and msi and nmi */ > - nr <<= 1; > - > - /* something wrong ? */ > - if (nr < nr_min) > - nr = nr_min; > - if (WARN_ON(nr > NR_IRQS)) > - nr = NR_IRQS; > - > - return nr; > + return NR_IRQS; > } > -- Med venlig hilsen / Best regards Jesper Brouer ComX Networks A/S Linux Network developer Cand. Scient Datalog / MSc. Author of http://adsl-optimizer.dk LinkedIn: http://www.linkedin.com/in/brouer