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From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>, Kevin Hilman <khilman@linaro.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Viresh Kumar <viresh.kumar@linaro.org>
Subject: Re: [PATCH 1/5] irq_work: Let arch tell us if it can raise irq work
Date: Tue, 13 May 2014 19:09:42 +0200	[thread overview]
Message-ID: <20140513170942.GC5226@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <1399991921-17618-2-git-send-email-fweisbec@gmail.com>

On Tue, May 13, 2014 at 04:38:37PM +0200, Frederic Weisbecker wrote:
> We prepare for executing the full nohz kick through an irq work. But
> if we do this as is, we'll run into conflicting tick locking: the tick
> holds the hrtimer lock and the nohz kick may do so too.

It does? How does the tick end up holding that lock?

Normal hrtimer callbacks run without holding the hrtimer lock -- I made
it so.

This means tick_sched_timer() is called without hrtimer lock, and I
don't see it taking it anywhere in tick_sched_do_timer() or
tick_sched_handle().

  reply	other threads:[~2014-05-13 17:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-13 14:38 [RFC PATCH 0/5] nohz: Move nohz kick out of scheduler IPI, v4 Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 1/5] irq_work: Let arch tell us if it can raise irq work Frederic Weisbecker
2014-05-13 17:09   ` Peter Zijlstra [this message]
2014-05-13 19:33     ` Frederic Weisbecker
2014-05-13 20:48       ` Peter Zijlstra
2014-05-13 21:15         ` Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 2/5] irq_work: Force non-lazy works to the IPI Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 3/5] irq_work: Allow remote queueing Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 4/5] nohz: Move full nohz kick to its own IPI Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 5/5] nohz: Use IPI implicit full barrier against rq->nr_running r/w Frederic Weisbecker

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