Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1037611AbdDUJ7P (ORCPT ); Fri, 21 Apr 2017 05:59:15 -0400 Received: from mail.santannapisa.it ([193.205.80.98]:56401 "EHLO mail.santannapisa.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1037514AbdDUJ7N (ORCPT ); Fri, 21 Apr 2017 05:59:13 -0400 Date: Fri, 21 Apr 2017 11:59:07 +0200 From: luca abeni To: Juri Lelli Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Claudio Scordino , Steven Rostedt , Tommaso Cucinotta , Daniel Bristot de Oliveira , Mathieu Poirier Subject: Re: [PATCH] sched/deadline: fix switching to -deadline Message-ID: <20170421115907.4044665a@nowhere> In-Reply-To: <20170421094729.GR23862@e106622-lin> References: <1492716656-5362-1-git-send-email-luca.abeni@santannapisa.it> <20170421093926.GQ23862@e106622-lin> <20170421114240.0ef43522@nowhere> <20170421094729.GR23862@e106622-lin> Organization: Scuola Superiore S.Anna 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 Content-Length: 976 Lines: 27 On Fri, 21 Apr 2017 10:47:29 +0100 Juri Lelli wrote: [...] > > > > *dl_se, update_dl_entity(dl_se, pi_se); > > > > else if (flags & ENQUEUE_REPLENISH) > > > > replenish_dl_entity(dl_se, pi_se); > > > > + else if ((flags & ENQUEUE_RESTORE) && > > > > > > Not sure I understand how this works. AFAICT we are doing > > > __sched_setscheduler() when we want to catch the case of a new > > > dl_entity (SCHED_{OTHER,FIFO} -> SCHED_DEADLINE}, but queue_flags > > > (which are passed to enqueue_task()) don't seem to have > > > ENQUEUE_RESTORE set? > > > > I was under the impression sched_setscheduler() sets > > ENQUEUE_RESTORE... > > Oh, I think it works "by coincidence", as ENQUEUE_RESTORE == > DEQUEUE_SAVE == 0x02 ? :) Not sure if this is a conincidence... By looking at the comments in sched/sched.h I got the impression the two values match by design (and __sched_setscheduler() is using this property to simplify the code :) Luca