From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753472Ab1JJKnF (ORCPT ); Mon, 10 Oct 2011 06:43:05 -0400 Received: from casper.infradead.org ([85.118.1.10]:53599 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753113Ab1JJKnD (ORCPT ); Mon, 10 Oct 2011 06:43:03 -0400 Subject: Re: [PATCH v2] CPU hotplug, freezer: Fix bugs in CPU hotplug call path From: Peter Zijlstra To: "Srivatsa S. Bhat" 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@lists.linux-foundation.org, rusty@rustcorp.com.au, vatsa@linux.vnet.ibm.com, ashok.raj@intel.com, linux-kernel@vger.kernel.org In-Reply-To: <4E8F6785.2010104@linux.vnet.ibm.com> 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> Content-Type: text/plain; charset="UTF-8" Date: Mon, 10 Oct 2011 12:48:59 +0200 Message-ID: <1318243739.14400.10.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.