Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762826AbZDHMq6 (ORCPT ); Wed, 8 Apr 2009 08:46:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754477AbZDHMqs (ORCPT ); Wed, 8 Apr 2009 08:46:48 -0400 Received: from viefep16-int.chello.at ([62.179.121.36]:12511 "EHLO viefep16-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752858AbZDHMqr (ORCPT ); Wed, 8 Apr 2009 08:46:47 -0400 X-SourceIP: 213.93.53.227 Subject: Re: pm-hibernate : possible circular locking dependency detected From: Peter Zijlstra To: Rusty Russell Cc: Ingo Molnar , "Rafael J. Wysocki" , Ming Lei , Andrew Morton , Linux-pm mailing list , Linux Kernel List , Gautham R Shenoy In-Reply-To: <200904081247.08712.rusty@rustcorp.com.au> References: <200904071356.29914.rusty@rustcorp.com.au> <1239087953.798.5513.camel@twins> <200904081247.08712.rusty@rustcorp.com.au> Content-Type: text/plain Date: Wed, 08 Apr 2009 14:48:26 +0200 Message-Id: <1239194906.13185.93.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1077 Lines: 26 On Wed, 2009-04-08 at 12:47 +0930, Rusty Russell wrote: > On Tuesday 07 April 2009 16:35:53 Peter Zijlstra wrote: > > On Tue, 2009-04-07 at 13:56 +0930, Rusty Russell wrote: > > > Looks like this will be fixed by Andrew's work-on-cpu-in-own-thread > > > patch which I just put out the pull request for. > > > > Would it make sense to teach it about a short-circuit like: > > > > work_on_cpu() { > > > > if (cpumask_weight(current->cpus_allowed) == 1 && > > smp_processor_id() == cpu) > > return do_work_right_here(); > > Does that happen much? I guess put a counter in and see? Ego spotted the case where cpufreq calls it from an cpu-affine workqueue, it seems to me in that case its desirable to have the short-cut, and currently that's needed for correctness too as it will generate this circular lock thingy. -- 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/