From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756842AbYIIStR (ORCPT ); Tue, 9 Sep 2008 14:49:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754335AbYIIStE (ORCPT ); Tue, 9 Sep 2008 14:49:04 -0400 Received: from mail-gx0-f16.google.com ([209.85.217.16]:64038 "EHLO mail-gx0-f16.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752762AbYIIStB (ORCPT ); Tue, 9 Sep 2008 14:49:01 -0400 Message-ID: <48C6C520.5070103@colorfullife.com> Date: Tue, 09 Sep 2008 20:49:04 +0200 From: Manfred Spraul User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: David Miller CC: paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, wli@holomorphy.com, sparclinux@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs References: <20080903004211.GD6748@linux.vnet.ibm.com> <20080903.022138.31681256.davem@davemloft.net> <20080903154217.GA6807@linux.vnet.ibm.com> <20080908.171708.43575256.davem@davemloft.net> In-Reply-To: <20080908.171708.43575256.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Miller wrote: > And IPI handler runs in HW irq context, therefore such an IPI-creates-an-IPI > should not be allowed, at least not directly. > > Actually the restriction seems to be that an IPI cannot be sent when > "irqs_disabled()", hmmm... > > Does this apply to smp_send_reschedule() as well? A [rare] codepath in the current rcu code does to trigger quiescent states on remote cpus. -- Manfred