From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751806AbWLMXdz (ORCPT ); Wed, 13 Dec 2006 18:33:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751805AbWLMXdz (ORCPT ); Wed, 13 Dec 2006 18:33:55 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:37339 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751802AbWLMXdy (ORCPT ); Wed, 13 Dec 2006 18:33:54 -0500 Date: Thu, 14 Dec 2006 00:31:57 +0100 From: Ingo Molnar To: "Siddha, Suresh B" Cc: nickpiggin@yahoo.com.au, vatsa@in.ibm.com, clameter@sgi.com, tglx@linutronix.de, arjan@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [RFC] Patch: dynticks: idle load balancing Message-ID: <20061213233157.GA20470@elte.hu> References: <20061211155304.A31760@unix-os.sc.intel.com> <20061213224317.GA2986@elte.hu> <20061213231316.GA13849@elte.hu> <20061213150314.B12795@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061213150314.B12795@unix-os.sc.intel.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.6 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.6 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Siddha, Suresh B wrote: > On Thu, Dec 14, 2006 at 12:13:16AM +0100, Ingo Molnar wrote: > > there's another bug as well: in schedule() resched_cpu() is called with > > the current runqueue held in two places, which is deadlock potential. > > resched_cpu() was getting called after prepare_task_switch() which > releases the current runqueue lock. Isn't it? no, it doesnt release it. The finish stage is what releases it. the other problem is load_balance(): there this_rq is locked and you call resched_cpu() unconditionally. Ingo