From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
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 <mingo@redhat.com>
Subject: Re: [PATCH -v2 2/9] sched/rtmutex/deadline: Fix a PI crash for deadline tasks
Date: Thu, 29 Sep 2016 10:49:27 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1609291048460.4825@nanos> (raw)
In-Reply-To: <20160926124127.932737914@infradead.org>
On Mon, 26 Sep 2016, Peter Zijlstra wrote:
> This is because rt_mutex_enqueue_pi() and rt_mutex_dequeue_pi()
> are only protected by pi_lock when operating pi waiters, while
> rt_mutex_get_top_task(), will access them with rq lock held but
> not holding pi_lock.
>
> In order to tackle it, we introduce new "pi_top_task" pointer
> cached in task_struct, and add new rt_mutex_update_top_task()
> to update its value, it can be called by rt_mutex_setprio()
> which held both owner's pi_lock and rq lock. Thus "pi_top_task"
> can be safely accessed by enqueue_task_dl() under rq lock.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
next prev parent reply other threads:[~2016-09-29 14:52 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-26 12:32 [PATCH -v2 0/9] PI and assorted failings Peter Zijlstra
2016-09-26 12:32 ` [PATCH -v2 1/9] rtmutex: Deboost before waking up the top waiter Peter Zijlstra
2016-09-26 15:15 ` Steven Rostedt
2016-09-26 15:22 ` Peter Zijlstra
2016-09-26 15:35 ` Steven Rostedt
2016-09-26 15:37 ` Steven Rostedt
2016-09-26 15:41 ` Peter Zijlstra
2016-09-29 14:43 ` Thomas Gleixner
2016-09-29 14:49 ` Peter Zijlstra
2016-09-26 15:39 ` Peter Zijlstra
2016-09-28 9:07 ` Sebastian Andrzej Siewior
2016-09-28 9:24 ` Peter Zijlstra
2016-09-26 12:32 ` [PATCH -v2 2/9] sched/rtmutex/deadline: Fix a PI crash for deadline tasks Peter Zijlstra
2016-09-26 15:20 ` Steven Rostedt
2016-09-26 15:26 ` Peter Zijlstra
2016-09-29 14:49 ` Thomas Gleixner [this message]
2016-09-26 12:32 ` [PATCH -v2 3/9] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update Peter Zijlstra
2016-09-26 16:03 ` Steven Rostedt
2016-09-29 14:48 ` Thomas Gleixner
2016-09-26 12:32 ` [PATCH -v2 4/9] rtmutex: Remove rt_mutex_fastunlock() Peter Zijlstra
2016-09-29 14:47 ` Thomas Gleixner
2016-09-26 12:32 ` [PATCH -v2 5/9] rtmutex: Clean up Peter Zijlstra
2016-09-26 16:09 ` Steven Rostedt
2016-09-29 14:51 ` Thomas Gleixner
2016-09-26 12:32 ` [PATCH -v2 6/9] sched/rtmutex: Refactor rt_mutex_setprio() Peter Zijlstra
2016-09-26 16:57 ` Steven Rostedt
2016-09-26 12:32 ` [PATCH -v2 7/9] sched,tracing: Update trace_sched_pi_setprio() Peter Zijlstra
2016-09-26 17:04 ` Steven Rostedt
2016-09-27 7:44 ` Peter Zijlstra
2016-09-26 12:32 ` [PATCH -v2 8/9] rtmutex: Fix PI chain order integrity Peter Zijlstra
2016-09-26 12:32 ` [PATCH -v2 9/9] rtmutex: Fix more prio comparisons Peter Zijlstra
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