From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751936AbaANOPY (ORCPT ); Tue, 14 Jan 2014 09:15:24 -0500 Received: from merlin.infradead.org ([205.233.59.134]:33616 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751812AbaANOOU (ORCPT ); Tue, 14 Jan 2014 09:14:20 -0500 Date: Tue, 14 Jan 2014 15:14:06 +0100 From: Peter Zijlstra To: Stephen Rothwell Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Mikulas Patocka Subject: Re: linux-next: build failure after merge of the tip tree Message-ID: <20140114141406.GD7572@laptop.programming.kicks-ass.net> References: <20140114142627.537a702607e703c6eff63640@canb.auug.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140114142627.537a702607e703c6eff63640@canb.auug.org.au> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 14, 2014 at 02:26:27PM +1100, Stephen Rothwell wrote: > Hi all, > > After merging the tip tree, today's linux-next build (x86_64 allmodconfig) > failed like this: > > drivers/cpufreq/speedstep-lib.c: In function 'speedstep_get_freqs': > drivers/cpufreq/speedstep-lib.c:467:2: error: implicit declaration of function 'preempt_check_resched' [-Werror=implicit-function-declaration] > preempt_check_resched(); > ^ > > Caused by commit 62b94a08da1b ("sched/preempt: Take away > preempt_enable_no_resched() from modules") interacting with commit > 24e1937b2386 ("speedstep-smi: enable interrupts when waiting") from the > pm tree. I think that pm commit is a very good example of why the sched/preempt patch is a very good idea. Also that Changelog fails to explain why enabling interrupts helps. What interrupt is required for progress, and how does it make the progress happen.