Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751116AbVISGgs (ORCPT ); Mon, 19 Sep 2005 02:36:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750863AbVISGgs (ORCPT ); Mon, 19 Sep 2005 02:36:48 -0400 Received: from smtp201.mail.sc5.yahoo.com ([216.136.129.91]:58780 "HELO smtp201.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S1750730AbVISGgr (ORCPT ); Mon, 19 Sep 2005 02:36:47 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Subject:From:To:Cc:In-Reply-To:References:Content-Type:Date:Message-Id:Mime-Version:X-Mailer:Content-Transfer-Encoding; b=CPcJ8oS3EwlOA9ESmgFMIKhLVyBJUjxRVjHWF0DfducF/GB7uHE75BtOk4C0MKPGzzVQof7INz/Qyv1gAn046woIve6/txAJ0PQb9lOxfxvYMo6Pl5f3pQStf0Rbn9fQ/fV4POj4IP5zJ/DCsU59RMS0QdtXtHCOaPAdbKNA4uE= ; Subject: Re: PATCH: Fix race in cpu_down (hotplug cpu) From: Nick Piggin To: Shaohua Li Cc: vatsa@in.ibm.com, Nigel Cunningham , Andrew Morton , Linus Torvalds , Zwane Mwaikambo , lkml , Rusty Russell , Ingo Molnar In-Reply-To: <1127111830.4087.3.camel@linux-hp.sh.intel.com> 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> Content-Type: text/plain Date: Mon, 19 Sep 2005 16:36:23 +1000 Message-Id: <1127111784.5272.10.camel@npiggin-nld.site> Mime-Version: 1.0 X-Mailer: Evolution 2.0.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 912 Lines: 27 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? Nick -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - 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/