From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753195Ab1K2HEU (ORCPT ); Tue, 29 Nov 2011 02:04:20 -0500 Received: from gate.crashing.org ([63.228.1.57]:52825 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802Ab1K2HET (ORCPT ); Tue, 29 Nov 2011 02:04:19 -0500 Message-ID: <1322550115.23348.72.camel@pasglop> Subject: Re: [RFC PATCH v2 1/4] cpuidle: (powerpc) Add cpu_idle_wait() to allow switching of idle routines From: Benjamin Herrenschmidt To: Deepthi Dharwar Cc: linuxppc-dev@ozlabs.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Date: Tue, 29 Nov 2011 18:01:55 +1100 In-Reply-To: <4ED47EC2.2090802@linux.vnet.ibm.com> References: <20111117112815.9191.2322.stgit@localhost6.localdomain6> <20111117112830.9191.1951.stgit@localhost6.localdomain6> <1322434096.23348.6.camel@pasglop> <4ED36A37.3030409@linux.vnet.ibm.com> <1322512522.23348.43.camel@pasglop> <4ED47EC2.2090802@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.1- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-11-29 at 12:12 +0530, Deepthi Dharwar wrote: > > Yes, this could be problematic as there is small window for the > race condition to occur . Otherwise we need to manually schedule > it by running a kernel thread but this would definitely have a > overhead and would be an overkill. Depends what this "window" is. IE. What are you trying to protect yourself against ? What's the risk ? If it's just module unload, then stop_machine is probably your friend :-) Cheers, Ben.