Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932177AbVISHG3 (ORCPT ); Mon, 19 Sep 2005 03:06:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932343AbVISHG3 (ORCPT ); Mon, 19 Sep 2005 03:06:29 -0400 Received: from fmr19.intel.com ([134.134.136.18]:64748 "EHLO orsfmr004.jf.intel.com") by vger.kernel.org with ESMTP id S932177AbVISHG2 (ORCPT ); Mon, 19 Sep 2005 03:06:28 -0400 Subject: Re: PATCH: Fix race in cpu_down (hotplug cpu) From: Shaohua Li To: Nick Piggin Cc: vatsa@in.ibm.com, Nigel Cunningham , Andrew Morton , Linus Torvalds , Zwane Mwaikambo , lkml , Rusty Russell , Ingo Molnar In-Reply-To: <1127111784.5272.10.camel@npiggin-nld.site> References: <59D45D057E9702469E5775CBB56411F171F7E0@pdsmsx406> <20050919051024.GA8653@in.ibm.com> <1127107887.3958.9.camel@linux-hp.sh.intel.com> <20050919055715.GE8653@in.ibm.com> <1127110271.9696.97.camel@localhost> <20050919062336.GA9466@in.ibm.com> <1127111830.4087.3.camel@linux-hp.sh.intel.com> <1127111784.5272.10.camel@npiggin-nld.site> Content-Type: text/plain Date: Mon, 19 Sep 2005 15:12:10 +0800 Message-Id: <1127113930.4087.6.camel@linux-hp.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1017 Lines: 25 On Mon, 2005-09-19 at 16:36 +1000, Nick Piggin wrote: > On Mon, 2005-09-19 at 14:37 +0800, Shaohua Li wrote: > > On Mon, 2005-09-19 at 11:53 +0530, Srivatsa Vaddagiri wrote: > > > > default_idle should be fine as it is. IOW it should not cause __cpu_die to > > > timeout. > > Why default_idle should be fine? it can be preempted before the > > 'local_irq_disable' check. Even with Nigel's patch, there is a very > > small window at safe_halt (after 'sti' but before 'hlt'). > > > > Ah, actually I have a patch which makes all CPU idle threads > run with preempt disabled and only enable preempt when scheduling. > Would that help? It should solve the issue to me. Should we take care of the latency? acpi_processor_idle might execute for a long time. Thanks, Shaohua - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/