From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751824AbWBXEEH (ORCPT ); Thu, 23 Feb 2006 23:04:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751837AbWBXEEH (ORCPT ); Thu, 23 Feb 2006 23:04:07 -0500 Received: from mx1.rowland.org ([192.131.102.7]:7949 "HELO mx1.rowland.org") by vger.kernel.org with SMTP id S1751824AbWBXEED (ORCPT ); Thu, 23 Feb 2006 23:04:03 -0500 Date: Thu, 23 Feb 2006 23:04:02 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Andi Kleen cc: sekharan@us.ibm.com, Subject: Re: [PATCH] The idle notifier chain should be atomic In-Reply-To: <200602240427.27441.ak@suse.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 24 Feb 2006, Andi Kleen wrote: > On Friday 24 February 2006 04:24, Alan Stern wrote: > > > In do_IRQ() there's a call to exit_idle(), which calls __exit_idle(), > > which runs the idle_notifier call chain. Surely you're not saying that we > > can do a down_read() in this pathway? > > No, but not because it's in an interrupt but because sleeping in the idle > task is illegal. Well, either reason is sufficient justification for making idle_notifier an atomic chain. > > And actually the chain's type doesn't seem to make much difference, since > > at the moment there's nothing in the vanilla kernel that registers for the > > idle_notifier chain. > > Will come eventually. Will that be just for x86_64 or for all architectures? Alan Stern