From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752622AbcLFI5Q (ORCPT ); Tue, 6 Dec 2016 03:57:16 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36208 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751803AbcLFI5P (ORCPT ); Tue, 6 Dec 2016 03:57:15 -0500 Date: Tue, 6 Dec 2016 09:57:07 +0100 From: luca abeni To: Peter Zijlstra Cc: Steven Rostedt , Daniel Bristot de Oliveira , linux-kernel@vger.kernel.org, Ingo Molnar , Juri Lelli , Claudio Scordino Subject: Re: [RFC v3 1/6] Track the active utilisation Message-ID: <20161206095707.1a809101@sweethome> In-Reply-To: <20161206083501.GW3092@twins.programming.kicks-ass.net> References: <1477317998-7487-1-git-send-email-luca.abeni@unitn.it> <1477317998-7487-2-git-send-email-luca.abeni@unitn.it> <20161025112916.67eb245c@utopia> <20161025095811.50a5856a@gandalf.local.home> <20161118142359.GK3142@twins.programming.kicks-ass.net> <20161205233005.54275bd6@sweethome> <20161206083501.GW3092@twins.programming.kicks-ass.net> Organization: university of trento X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Dec 2016 09:35:01 +0100 Peter Zijlstra wrote: > On Mon, Dec 05, 2016 at 11:30:05PM +0100, luca abeni wrote: > > Hi Peter, > > > > On Fri, 18 Nov 2016 15:23:59 +0100 > > Peter Zijlstra wrote: > > [...] > > > u64 running_bw; > > > > > > static void add_running_bw(struct sched_dl_entity *dl_se, struct > > > dl_rq *dl_rq) { > > > u64 old = dl_rq->running_bw; > > > > > > dl_rq->running_bw += dl_se->dl_bw; > > > SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ > > > } > > > > > > static void sub_running_bw(struct sched_dl_entity *dl_se, struct > > > dl_rq *dl_rq) { > > > u64 old = dl_rq->running_bw; > > > > > > dl_rq->running_bw -= dl_se->dl_bw; > > > SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ > > > } > > > > I wanted to change "SCHED_WARN_ON(dl_rq->running_bw > old); /* > > underflow */" into "if (SCHED_WARN_ON(...)) dl_rq->running_bw = > > 0" (to avoid using nonsensical "running_bw" values), but I see that > > "SCHED_WARN_ON()" cannot be used inside an if (this seems to be a > > difference respect to "SCHED_WARN()"). > > There's a SCHED_WARN? Did you mean to say WARN_ON()? Sorry, I managed to confuse myself... I was thinking about WARN_ON() (the one I used in the previous version of my patches). > And yes, mostly by accident I think, I'm not a big user of that > pattern and neglected it when I did SCHED_WARN_ON(). You mean the "if(WARN(...))" pattern? I think it was suggested in a previous round of reviews. > > This is because of the definition used when CONFIG_SCHED_DEBUG is > > not defined (I noticed the issue when testing with random kernel > > configurations). > > I'm fine changing the definition, just find something that works. The > current ((void)(x)) thing was to avoid unused complaints -- although > I'm not sure there were any. Ok; I'll see if I manage to find a working definition. Thanks, Luca