From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034890AbcIZMow (ORCPT ); Mon, 26 Sep 2016 08:44:52 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:51849 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034316AbcIZMou (ORCPT ); Mon, 26 Sep 2016 08:44:50 -0400 Message-Id: <20160926124127.999595184@infradead.org> User-Agent: quilt/0.63-1 Date: Mon, 26 Sep 2016 14:32:16 +0200 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de, juri.lelli@arm.com, rostedt@goodmis.org, xlpang@redhat.com, bigeasy@linutronix.de Cc: linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, jdesfossez@efficios.com, bristot@redhat.com, peterz@infradead.org, Ingo Molnar Subject: [PATCH -v2 3/9] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update References: <20160926123213.851818224@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=xunlei_pang-sched_deadline_rtmutex-don_t_miss_the_dl_runtime_dl_period_update.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently dl tasks will actually return at the very beginning of rt_mutex_adjust_prio_chain() in !detect_deadlock cases: if (waiter->prio == task->prio) { if (!detect_deadlock) goto out_unlock_pi; // out here else requeue = false; } As the deadline value of blocked deadline tasks(waiters) without changing their sched_class(thus prio doesn't change) never changes, this seems reasonable, but it actually misses the chance of updating rt_mutex_waiter's "dl_runtime(period)_copy" if a waiter updates its deadline parameters(dl_runtime, dl_period) or boosted waiter changes to !deadline class. Thus, force deadline task not out by adding the !dl_prio() condition. Cc: Steven Rostedt Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Juri Lelli Signed-off-by: Xunlei Pang Signed-off-by: Peter Zijlstra (Intel) Link: http://lkml.kernel.org/r/1460633827-345-7-git-send-email-xlpang@redhat.com --- kernel/locking/rtmutex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -488,7 +488,7 @@ static int rt_mutex_adjust_prio_chain(st * enabled we continue, but stop the requeueing in the chain * walk. */ - if (waiter->prio == task->prio) { + if (waiter->prio == task->prio && !dl_task(task)) { if (!detect_deadlock) goto out_unlock_pi; else