From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262159AbULLWlk (ORCPT ); Sun, 12 Dec 2004 17:41:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262160AbULLWlj (ORCPT ); Sun, 12 Dec 2004 17:41:39 -0500 Received: from dbl.q-ag.de ([213.172.117.3]:26061 "EHLO dbl.q-ag.de") by vger.kernel.org with ESMTP id S262159AbULLWlh (ORCPT ); Sun, 12 Dec 2004 17:41:37 -0500 Message-ID: <41BCC8F8.3030102@colorfullife.com> Date: Sun, 12 Dec 2004 23:40:56 +0100 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr-FR; rv:1.7.3) Gecko/20040922 X-Accept-Language: en-us, en MIME-Version: 1.0 To: george@mvista.com CC: Andrea Arcangeli , Zwane Mwaikambo , Lee Revell , dipankar@in.ibm.com, ganzinger@mvista.com, lkml Subject: Re: RCU question References: <41BA0ECF.1060203@mvista.com> <41BA59F6.5010309@mvista.com> <41BA698E.8000603@mvista.com> <41BB2108.70606@colorfullife.com> <41BB25B2.90303@mvista.com> <41BC0854.4010503@colorfullife.com> <20041212093714.GL16322@dualathlon.random> <41BC1BF9.70701@colorfullife.com> <41BC771D.6020506@mvista.com> In-Reply-To: <41BC771D.6020506@mvista.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org George Anzinger wrote: > > The "normal" idle loop just looks at the need_resched flag and goes > right back to the hlt, That's the problem: If a the tasklet does a wakeup then the reschedule is delayed until the next interrupt. Testing need_resched and executing hlt must be atomic, but it isn't - NMIs break the atomicity. Not a big deal, except if someone implements a tickless kernel. I think we can ignore it for now [or was the thread started by someone who want's to disable the hardware timer when the system is really idle?] -- Manfred