Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758726AbYGaTz2 (ORCPT ); Thu, 31 Jul 2008 15:55:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752064AbYGaTzP (ORCPT ); Thu, 31 Jul 2008 15:55:15 -0400 Received: from py-out-1112.google.com ([64.233.166.181]:19731 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750968AbYGaTzN (ORCPT ); Thu, 31 Jul 2008 15:55:13 -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=HYeb9G0AucmKGiIVddOGeU43ptU18ejN8wteDYNDFGUNwryFBjZyTvLBb59ykVqmAS ZKPffavLplFJAh/i4M6FWiNyI8GOO8i9U68cNXr+1+Y6AhbF+/t/5pgds15XOUZyKdKm nIi2jR1J2PYzyKjWEYZjEhZxbO+Iobo87VSyA= Message-ID: Date: Thu, 31 Jul 2008 21:55:11 +0200 From: "Dmitry Adamushko" To: "Ingo Molnar" Subject: Re: Oops in microcode sysfs registration, Cc: "Alistair John Strachan" , "Pekka Paalanen" , "Linus Torvalds" , "Linux Kernel Mailing List" , shaohua.li@intel.com, tigran@aivazian.fsnet.co.uk, "Thomas Gleixner" , "Steven Rostedt" , "Max Krasnyansky" , "Peter Zijlstra" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200807291457.58408.alistair@devzero.co.uk> <20080729192214.2d3a4ca5@daedalus.pq.iki.fi> <200807291750.41169.alistair@devzero.co.uk> <20080731165650.GJ26393@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1763 Lines: 46 2008/7/31 Dmitry Adamushko : >> >> could you please send this patch with a changelog, explanation, etc.? > > Now having thought a bit more on that issue, I tend to think that this > patch is not all that nice (so I agree with Max here). > > The root problem is the way set_cpus_allowed_ptr() is used in > microcode's cpu-hotplug handler. With cpu_active_map in place > set_cpus_allowed_ptr() can't migrate a task on the soon-to-be-online > cpu from withing a CPU_ONLINE handler (more in details here: > http://lkml.org/lkml/2008/7/24/260) > > Basically, this patch marks a 'cpu' available for other tasks to be > migrated to it before sending CPU_ONLINE notification to > subscribers... [ now, there can be CPU_ONLINE > http://lkml.org/lkml/2008/7/24/260handlers that has something to do > with enabling migration/load-balancing. e.g. migration_call() , > although it has the highest prio and is supposed to run first in a > chain ] > > In another thread, I've asked whether doing 'microcode update' in > start_secondary() (or even at the beginning of idle_cpu() would be > better): > > pros: > - it's done as early as possible (no other tasks has started running > on a cpu yet); > - no actions in cpu-hotplug; > > cons: > - microcode sub-systems becomes visible outside of microcode.c _but_ > it's arch-specific part anyway + with object-oriented re-work (which > is in -tip), I think it'd be that bad. it was supposed to be "it'd be _not_ that bad" -- Best regards, Dmitry Adamushko -- 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/