From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932897AbdBVOjX (ORCPT ); Wed, 22 Feb 2017 09:39:23 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:58846 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932700AbdBVOjO (ORCPT ); Wed, 22 Feb 2017 09:39:14 -0500 Date: Wed, 22 Feb 2017 15:39:10 +0100 From: Peter Zijlstra To: Alex Shi Cc: Mike Galbraith , LKML , "Rafael J. Wysocki" , Rik van Riel Subject: Re: 9908859acaa9 cpuidle/menu: add per CPU PM QoS resume latency consideration Message-ID: <20170222143910.GV6515@twins.programming.kicks-ass.net> References: <1487768197.27533.5.camel@gmx.de> <20170222131218.GS6515@twins.programming.kicks-ass.net> <1487769542.4487.2.camel@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 22, 2017 at 10:31:26PM +0800, Alex Shi wrote: > > > On 02/22/2017 09:19 PM, Mike Galbraith wrote: > > On Wed, 2017-02-22 at 14:12 +0100, Peter Zijlstra wrote: > >> On Wed, Feb 22, 2017 at 01:56:37PM +0100, Mike Galbraith wrote: > >>> Hi, > >>> > >>> Do we really need a spinlock for that in the idle loop? > >> > >> Urgh, that's broken on RT, you cannot schedule the idle loop. > > > > That's what made me notice the obnoxious little bugger. > > Hi Mike, > > Sorry for this bug. Guess the rt_spin_lock call some function in > rtmutex.c:995. Could you like to show me how to reproduce this bug? Its not hard; spinlock_t ends up being a mutex, and this is ran from the idle thread. What thread do you think we ought to run when we block idle?