From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754493Ab1JULa0 (ORCPT ); Fri, 21 Oct 2011 07:30:26 -0400 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:57704 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752259Ab1JULaZ (ORCPT ); Fri, 21 Oct 2011 07:30:25 -0400 Message-ID: <4EA157C9.30500@linux.vnet.ibm.com> Date: Fri, 21 Oct 2011 17:00:17 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux i686; rv:7.0) Gecko/20110927 Thunderbird/7.0 MIME-Version: 1.0 To: Peter Zijlstra CC: "Rafael J. Wysocki" , pavel@ucw.cz, len.brown@intel.com, mingo@elte.hu, akpm@linux-foundation.org, suresh.b.siddha@intel.com, lucas.demarchi@profusion.mobi, "linux-pm@vger.kernel.org >> Linux PM mailing list" , rusty@rustcorp.com.au, vatsa@linux.vnet.ibm.com, ashok.raj@intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] CPU hotplug, freezer: Fix bugs in CPU hotplug call path References: <4E88BF33.10407@linux.vnet.ibm.com> <1317636215.12973.16.camel@twins> <4E8B07EA.4020307@linux.vnet.ibm.com> <4E8B09F3.4080800@linux.vnet.ibm.com> <1317735440.32543.4.camel@twins> <4E8F6785.2010104@linux.vnet.ibm.com> <1318243739.14400.10.camel@laptop> In-Reply-To: <1318243739.14400.10.camel@laptop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/10/2011 04:18 PM, Peter Zijlstra wrote: > On Sat, 2011-10-08 at 02:26 +0530, Srivatsa S. Bhat wrote: >> >> So, we should mutually exclude cpu hotplugging and freezing/thawing to >> ensure that during the entire duration that the callbacks for the notified >> event are running, the state introduced by that event holds good. > > Yes we should, but I'd rather see that done on a more fundamental level, > and not frob yet another mutex in the already complex hotplug system. > Sure, thank you for the feedback. I have now come up with another version that doesn't introduce any new mutex. I'll post it out in a while. -- Regards, Srivatsa S. Bhat Linux Technology Center, IBM India Systems and Technology Lab