From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592AbcGLImX (ORCPT ); Tue, 12 Jul 2016 04:42:23 -0400 Received: from foss.arm.com ([217.140.101.70]:57491 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750794AbcGLImU (ORCPT ); Tue, 12 Jul 2016 04:42:20 -0400 Date: Tue, 12 Jul 2016 09:42:47 +0100 From: Juri Lelli To: xlpang@redhat.com Cc: luca abeni , peterz@infradead.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, mingo@redhat.com Subject: Re: [PATCH v3] sched/deadline: remove useless param from setup_new_dl_entity Message-ID: <20160712084247.GB30652@e106622-lin> References: <1467977331-31116-1-git-send-email-juri.lelli@arm.com> <578328BC.3080504@redhat.com> <20160711100151.69940aff@utopia> <578355D4.9080007@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <578355D4.9080007@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/07/16 16:16, Xunlei Pang wrote: > On 2016/07/11 at 16:01, luca abeni wrote: > > Hello, > > > > On Mon, 11 Jul 2016 13:03:56 +0800 > > Xunlei Pang wrote: > > > >> On 2016/07/08 at 19:28, Juri Lelli wrote: > > [...] > >>> @@ -363,6 +364,15 @@ static inline void setup_new_dl_entity(struct > >>> sched_dl_entity *dl_se, return; > >>> > >>> /* > >>> + * Use the scheduling parameters of the top pi-waiter task, > >>> + * if we have one from which we can inherit a deadline. > >>> + */ > >>> + if (dl_se->dl_boosted && > >>> + (pi_task = rt_mutex_get_top_task(dl_task_of(dl_se))) && > >>> + dl_prio(pi_task->normal_prio)) > >>> + pi_se = &pi_task->dl; > >>> + > >>> + /* > >>> * We use the regular wall clock time to set deadlines in > >>> the > >>> * future; in fact, we must consider execution overheads > >>> (time > >>> * spent on hardirq context, etc.). > >>> @@ -1721,7 +1731,7 @@ static void switched_from_dl(struct rq *rq, > >>> struct task_struct *p) static void switched_to_dl(struct rq *rq, > >>> struct task_struct *p) { > >>> if (dl_time_before(p->dl.deadline, rq_clock(rq))) > >>> - setup_new_dl_entity(&p->dl, &p->dl); > >>> + setup_new_dl_entity(&p->dl); > >> I'm curious why we even call setup_new_dl_entity() for non-queued > >> cases? It seems more reasonable to do it when it really gets queued. > >> We can see that enqueue_task_dl()->update_dl_entity() also has the > >> same update logic as switched_to_dl(). > > I wondered the same when removing the dl_new field from > > sched_dl_entity... But then I realised that enqueue_dl_entity() does > > not always invoke update_dl_entity() or replenish_dl_entity()... For > > example, when a task switches from SCHED_OTHER (or RT) to -deadline due > > to sched_setattr() (or similar) these functions are not invoked. > > Yeah, but for wake-up cases it does, as ENQUEUE_WAKEUP is set. > What I meant is, can we only update for queued tasks in switched_to_dl()? > Looks sensible to do. I think we can use the already present task_on_rq_queued() check in there. I'll put together a v4 ASAP (if Luca doesn't have already something). Thanks, - Juri