From patchwork Fri Jul 8 11:28:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juri Lelli X-Patchwork-Id: 71671 Delivered-To: patch@linaro.org Received: by 10.140.28.4 with SMTP id 4csp399682qgy; Fri, 8 Jul 2016 04:29:08 -0700 (PDT) X-Received: by 10.98.80.79 with SMTP id e76mr9112025pfb.67.1467977341170; Fri, 08 Jul 2016 04:29:01 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id q8si4852716pac.287.2016.07.08.04.29.00; Fri, 08 Jul 2016 04:29:01 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754783AbcGHL27 (ORCPT + 30 others); Fri, 8 Jul 2016 07:28:59 -0400 Received: from foss.arm.com ([217.140.101.70]:41954 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755072AbcGHL2q (ORCPT ); Fri, 8 Jul 2016 07:28:46 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4774428; Fri, 8 Jul 2016 04:29:46 -0700 (PDT) Received: from e106622-lin.cambridge.arm.com (e106622-lin.cambridge.arm.com [10.1.208.152]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B40653F41F; Fri, 8 Jul 2016 04:28:44 -0700 (PDT) From: Juri Lelli To: peterz@infradead.org Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, mingo@redhat.com, luca.abeni@unitn.it, juri.lelli@arm.com Subject: [PATCH v3] sched/deadline: remove useless param from setup_new_dl_entity Date: Fri, 8 Jul 2016 12:28:51 +0100 Message-Id: <1467977331-31116-1-git-send-email-juri.lelli@arm.com> X-Mailer: git-send-email 2.7.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org setup_new_dl_entity() takes two parameters, but it only actually uses one of them, under a different name, to setup a new dl_entity, after: 2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity" as we currently do setup_new_dl_entity(&p->dl, &p->dl) However, before Luca's change we were doing setup_new_dl_entity(dl_se, pi_se) in update_dl_entity() for a dl_se->new entity: we were using pi_se's parameters (the potential PI donor) for setting up a new entity. Restore this behaviour (as we want to correctly initialize parameters of a boosted task that enters DEADLINE) by removing the useless second parameter of setup_new_dl_entity() and retrieving the top waiter directly from inside that function. Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Luca Abeni Signed-off-by: Juri Lelli --- Changes from v2: - optimize by calling rt_mutex_get_top_task only if the task is boosted (as suggested by Steve) Changes from v1: - Steve pointed out that we were actually using the second parameter to permorm initialization - Luca confirmed that behavior is slightly changed w.r.t. before his change - changelog updated and original behavior restored --- kernel/sched/deadline.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) -- 2.7.4 diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index fcb7f0217ff4..7aeb21963d3c 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -346,11 +346,12 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, * one, and to (try to!) reconcile itself with its own scheduling * parameters. */ -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, - struct sched_dl_entity *pi_se) +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) { struct dl_rq *dl_rq = dl_rq_of_se(dl_se); struct rq *rq = rq_of_dl_rq(dl_rq); + struct task_struct *pi_task; + struct sched_dl_entity *pi_se = dl_se; WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); @@ -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); if (task_on_rq_queued(p) && rq->curr != p) { #ifdef CONFIG_SMP