Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756879AbYHKUM2 (ORCPT ); Mon, 11 Aug 2008 16:12:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752989AbYHKUMQ (ORCPT ); Mon, 11 Aug 2008 16:12:16 -0400 Received: from wr-out-0506.google.com ([64.233.184.226]:45331 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbYHKUMP (ORCPT ); Mon, 11 Aug 2008 16:12:15 -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=gzc/lxriQrxYmuT2TSU6yqMCsPTmvIgPaeiTS9KimOpcl4rYyGQyPzpqnS627DGH0z WOYp2I6LoQgabEBBjmhhiPcxa4Dq9r7KromKGcOklF+V40S5sVcEPElx3jH8FOlOCO7c 6kHLpSScAFn9qTjar1rUDBdgv7j29cHX76vU8= Message-ID: <86802c440808111312n49ce2c0akae18b539ad543410@mail.gmail.com> Date: Mon, 11 Aug 2008 13:12:14 -0700 From: "Yinghai Lu" To: "Ingo Molnar" Subject: Re: 2.6.27rc1 cannot boot more than 8CPUs Cc: "Jeff Chua" , "Linus Torvalds" , "David Miller" , "Max Krasnyansky" , "Li Zefan" , lkml In-Reply-To: <20080811200808.GB24111@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080811195939.GA16716@elte.hu> <86802c440808111303x16922f43g4e17fa43972e9076@mail.gmail.com> <20080811200808.GB24111@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2562 Lines: 61 On Mon, Aug 11, 2008 at 1:08 PM, Ingo Molnar wrote: > > * Yinghai Lu wrote: > >> On Mon, Aug 11, 2008 at 12:59 PM, Ingo Molnar wrote: >> > >> > * Jeff Chua wrote: >> > >> >> On Wed, Aug 6, 2008 at 2:42 PM, Jeff Chua wrote: >> >> > On Wed, Aug 6, 2008 at 2:01 PM, Linus Torvalds >> >> > wrote: >> >> >> One trivial thing to try would be to just bisect it. I assume 2.6.26 is >> >> > Bisecting now. >> >> >> >> Thanks to all the great helpful suggestions from everyone, and this >> >> turns out that I just need to enable the following switches, so I >> >> didn't bisect further, and since it's first machine that I've tried >> >> with more than 8 CPUs so I wasn't sure whether 2.6.16 has the same >> >> problem, but if you wish, I could give 2.6.16 a try. >> >> >> >> > CONFIG_X86_GENERICARCH=y >> >> > CONFIG_X86_BIGSMP=y >> >> >> >> Thank you all for the great linux kernel! >> > >> > i still consider a silent boot hang a bug we need to fix. >> > >> > bigsmp might be required to have all cpus available on your box, but the >> > kernel is still supposed to transparently fall back to less CPUs (and >> > print a warning) if it cannot do that. >> > >> in setup.c::setup_arch() after go over with madt or mptable >> >> #if defined(CONFIG_SMP) && defined(CONFIG_X86_PC) && defined(CONFIG_X86_32) >> if (def_to_bigsmp) >> printk(KERN_WARNING "More than 8 CPUs detected and " >> "CONFIG_X86_PC cannot handle it.\nUse " >> "CONFIG_X86_GENERICARCH or >> CONFIG_X86_BIGSMP.\n"); ===> here need to change "or" to "and" >> #endif >> >> or just panic here? because screen scroll to pass it, and user will >> not notice that... > > a panic is better but still quite rude and doesnt give a user a system > under which he can build an even greater kernel [after having discovered > the warning in the syslog] ;-) > > best would be to use as many CPUs as we can support, and skip the rest > and boot up fine. (and print the warning prominently - the user does not > make maximum use of available physical resources) then smp start AP cpu could check the apic id >=8 etc before try to start it.in some cases 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/