From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, tglx@linutronix.de, juri.lelli@arm.com,
xlpang@redhat.com, linux-kernel@vger.kernel.org,
mathieu.desnoyers@efficios.com, jdesfossez@efficios.com,
bristot@redhat.com, Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC][PATCH 3/8] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update
Date: Wed, 15 Jun 2016 12:30:07 -0400 [thread overview]
Message-ID: <20160615123007.728b088c@grimm.local.home> (raw)
In-Reply-To: <20160607200215.788266764@infradead.org>
On Tue, 07 Jun 2016 21:56:38 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
> From: Xunlei Pang <xlpang@redhat.com>
>
> 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.
>
> [peterz: I should introduce more task state comparators like
> rt_mutex_waiter_less, all PI prio comparisons already have this DL
> exception, except this one]
>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Juri Lelli <juri.lelli@arm.com>
> Signed-off-by: Xunlei Pang <xlpang@redhat.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> 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)) {
Isn't task the owner of the lock? What happens if the waiter is a
deadline task?
-- Steve
> if (!detect_deadlock)
> goto out_unlock_pi;
> else
>
next prev parent reply other threads:[~2016-06-15 16:30 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 19:56 [RFC][PATCH 0/8] PI and assorted failings Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 1/8] rtmutex: Deboost before waking up the top waiter Peter Zijlstra
2016-06-14 9:09 ` Juri Lelli
2016-06-14 12:54 ` Peter Zijlstra
2016-06-14 13:20 ` Juri Lelli
2016-06-14 13:59 ` Peter Zijlstra
2016-06-14 16:36 ` Davidlohr Bueso
2016-06-14 17:01 ` Juri Lelli
2016-06-14 18:22 ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 2/8] sched/rtmutex/deadline: Fix a PI crash for deadline tasks Peter Zijlstra
2016-06-14 10:21 ` Juri Lelli
2016-06-14 12:30 ` Peter Zijlstra
2016-06-14 12:53 ` Xunlei Pang
2016-06-14 13:07 ` Juri Lelli
2016-06-14 16:39 ` Juri Lelli
2016-06-14 18:42 ` Steven Rostedt
2016-06-14 20:28 ` Peter Zijlstra
2016-06-15 16:14 ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 3/8] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update Peter Zijlstra
2016-06-14 10:43 ` Juri Lelli
2016-06-14 12:09 ` Peter Zijlstra
2016-06-15 16:30 ` Steven Rostedt [this message]
2016-06-15 17:55 ` Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 4/8] rtmutex: Remove rt_mutex_fastunlock() Peter Zijlstra
2016-06-15 16:43 ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 5/8] rtmutex: Clean up Peter Zijlstra
2016-06-14 12:08 ` Juri Lelli
2016-06-14 12:32 ` Peter Zijlstra
2016-06-14 12:41 ` Juri Lelli
2016-06-07 19:56 ` [RFC][PATCH 6/8] sched/rtmutex: Refactor rt_mutex_setprio() Peter Zijlstra
2016-06-14 13:14 ` Juri Lelli
2016-06-14 14:08 ` Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 7/8] sched,tracing: Update trace_sched_pi_setprio() Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 8/8] rtmutex: Fix PI chain order integrity Peter Zijlstra
2016-06-14 17:39 ` Juri Lelli
2016-06-14 19:44 ` Peter Zijlstra
2016-06-15 7:25 ` Juri Lelli
2016-06-27 12:23 ` Peter Zijlstra
2016-06-27 12:40 ` Thomas Gleixner
2016-06-28 9:05 ` Juri Lelli
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