From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356AbYHBDnT (ORCPT ); Fri, 1 Aug 2008 23:43:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751532AbYHBDnJ (ORCPT ); Fri, 1 Aug 2008 23:43:09 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:46571 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751474AbYHBDnI (ORCPT ); Fri, 1 Aug 2008 23:43:08 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: "Yinghai Lu" Cc: "Ingo Molnar" , "Thomas Gleixner" , "H. Peter Anvin" , "Dhaval Giani" , "Mike Travis" , "Andrew Morton" , linux-kernel@vger.kernel.org References: <1217642575-22727-1-git-send-email-yhlu.kernel@gmail.com> <86802c440808011916q1a279ael995eaeaa655c239@mail.gmail.com> <86802c440808012011s109b27bbvb49e1794f66d9acc@mail.gmail.com> Date: Fri, 01 Aug 2008 20:37:34 -0700 In-Reply-To: <86802c440808012011s109b27bbvb49e1794f66d9acc@mail.gmail.com> (Yinghai Lu's message of "Fri, 1 Aug 2008 20:11:43 -0700") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SA-Exim-Connect-IP: 24.130.11.59 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-DCC: XMission; sa04 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;"Yinghai Lu" X-Spam-Relay-Country: X-Spam-Report: * -1.8 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% * [score: 0.0006] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa04 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 XM_SPF_Neutral SPF-Neutral Subject: Re: [PATCH] x86: 64bit support more than 256 irq v2 X-SA-Exim-Version: 4.2 (built Thu, 03 Mar 2005 10:44:12 +0100) X-SA-Exim-Scanned: Yes (on mgr1.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Yinghai Lu" writes: > On Fri, Aug 1, 2008 at 7:58 PM, Eric W. Biederman wrote: >> "Yinghai Lu" writes: >> >>> On Fri, Aug 1, 2008 at 7:02 PM, Yinghai Lu wrote: >>>> Dhaval Giani got: >>>> kernel BUG at arch/x86/kernel/io_apic_64.c:357! >>>> invalid opcode: 0000 [1] SMP >>>> CPU 24 >>>> ... >>>> >>>> his system (x3950) has 8 ioapic, irq > 256 > .. >> >> There was a patch that came out a while ago that set NR_IRQS as NR_IOAPICS*32 > from >> SGI. Where that got to I don't recall. > > #ifdef CONFIG_X86_32 > # define MAX_IO_APICS 64 > #else > # define MAX_IO_APICS 128 > # define MAX_LOCAL_APIC 32768 > #endif > > so they can take 128*32 = 4096? Yes. The real problem was just the complete explosion of irqs on SGI machines that have paltry I/O to the outside world compared to their cpu count. Have 131072 irqs seemed a little much for them. It is all a game of tuning heuristics right now, and if we can totally kill NR_IRQS it all goes away. But that is an issue to solve before the next merge window not to kill the regression. Eric