From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933050AbcI2Ouz (ORCPT ); Thu, 29 Sep 2016 10:50:55 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:55730 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933608AbcI2Out (ORCPT ); Thu, 29 Sep 2016 10:50:49 -0400 Date: Thu, 29 Sep 2016 10:48:13 -0400 (EDT) From: Thomas Gleixner To: Peter Zijlstra cc: mingo@kernel.org, juri.lelli@arm.com, rostedt@goodmis.org, xlpang@redhat.com, bigeasy@linutronix.de, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, jdesfossez@efficios.com, bristot@redhat.com, Ingo Molnar Subject: Re: [PATCH -v2 3/9] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update In-Reply-To: <20160926124127.999595184@infradead.org> Message-ID: References: <20160926123213.851818224@infradead.org> <20160926124127.999595184@infradead.org> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 Sep 2016, Peter Zijlstra wrote: > 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. Reviewed-by: Thomas Gleixner