Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753758Ab2FLQpj (ORCPT ); Tue, 12 Jun 2012 12:45:39 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55402 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366Ab2FLQpi convert rfc822-to-8bit (ORCPT ); Tue, 12 Jun 2012 12:45:38 -0400 Message-ID: <1339519530.31548.88.camel@twins> Subject: Re: Kernel panic - not syncing: Attempted to kill the idle task! From: Peter Zijlstra To: Linus Torvalds Cc: hi3766691@gmail.com, Hillf Danton , LKML , Andrea Arcangeli , Zhouping Liu Date: Tue, 12 Jun 2012 18:45:30 +0200 In-Reply-To: References: <1339421268.30462.15.camel@twins> <4FD6BD72.2070808@redhat.com> <1339490988.31548.40.camel@twins> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 894 Lines: 20 On Tue, 2012-06-12 at 13:20 +0300, Linus Torvalds wrote: > you are very fundamentally wrong if you think the distance array has > to be symmetric. I just checked, both QPI and HT are bi-directional links so anything mid-sized x86 had better be symmetric. Big numa can of course stick in their own interconnects and might do uni-directional stuff, although I doubt anybody still does that. The distance table I have for a 4096 cpu SGI machine is fully symmetric for instance. This of course doesn't mean we should make hard assumptions about this in the scheduler -- and we don't. But in this case it does mean the HP table is very funny indeed. -- 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/