Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754801AbdIGKKZ (ORCPT ); Thu, 7 Sep 2017 06:10:25 -0400 Received: from mail.sssup.it ([193.205.80.98]:55497 "EHLO mail.santannapisa.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754550AbdIGKKX (ORCPT ); Thu, 7 Sep 2017 06:10:23 -0400 From: luca abeni To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Juri Lelli , Steven Rostedt , Daniel Bristot de Oliveira , Mathieu Poirier , luca abeni Subject: [PATCH 2/4] sched/deadline: fix switching to -deadline Date: Thu, 7 Sep 2017 12:09:29 +0200 Message-Id: <1504778971-13573-3-git-send-email-luca.abeni@santannapisa.it> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1504778971-13573-1-git-send-email-luca.abeni@santannapisa.it> References: <1504778971-13573-1-git-send-email-luca.abeni@santannapisa.it> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1856 Lines: 52 Fix a bug introduced in 72f9f3fdc928dc3ecd223e801b32d930b662b6ed: after that commit, when switching to -deadline if the scheduling deadline of a task is in the past then switched_to_dl() calls setup_new_entity() to properly initialize the scheduling deadline and runtime. The problem is that the task is enqueued _before_ having its parameters initialized by setup_new_entity(), and this can cause problems. For example, a task with its out-of-date deadline in the past will potentially be enqueued as the highest priority one; however, its adjusted deadline may not be the earliest one. This patch fixes the problem by initializing the task's parameters before enqueuing it. Signed-off-by: luca abeni Reviewed-by: Daniel Bristot de Oliveira --- kernel/sched/deadline.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index d05bd94..d7f9e86 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1376,6 +1376,10 @@ enqueue_dl_entity(struct sched_dl_entity *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) && + dl_time_before(dl_se->deadline, + rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { + setup_new_dl_entity(dl_se); } __enqueue_dl_entity(dl_se); @@ -2267,13 +2271,6 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) return; } - /* - * If p is boosted we already updated its params in - * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH), - * p's deadline being now already after rq_clock(rq). - */ - if (dl_time_before(p->dl.deadline, rq_clock(rq))) - setup_new_dl_entity(&p->dl); if (rq->curr != p) { #ifdef CONFIG_SMP -- 2.7.4